Materials for organic electroluminescent devices

ABSTRACT

The present invention relates to compounds of the formula (1) which are suitable for use in electronic devices, in particular organic electroluminescent devices, and to electronic devices which comprise these compounds.

The present invention relates to a compound of the formula (1), to theuse of the compound in an electronic device, and to an electronic devicecomprising a compound of the formula (1). The present inventionfurthermore relates to a process for the preparation of a compound ofthe formula (1) and to a formulation comprising one or more compounds ofthe formula (1).

The development of functional compounds for use in electronic devices iscurrently the subject of intensive research. The aim is, in particular,the development of compounds with which improved properties ofelectronic devices in one or more relevant points can be achieved, suchas, for example, power efficiency and lifetime of the device as well ascolour coordinates of the emitted light.

In accordance with the present invention, the term electronic device istaken to mean, inter alia, organic integrated circuits (OICs), organicfield-effect transistors (OFETs), organic thin-film transistors (OTFTs),organic light-emitting transistors (OLETs), organic solar cells (OSCs),organic optical detectors, organic photoreceptors, organic field-quenchdevices (OFQDs), organic light-emitting electrochemical cells (OLECs),organic laser diodes (O-lasers) and organic electroluminescent devices(OLEDs).

Of particular interest is the provision of compounds for use in thelast-mentioned electronic devices called OLEDs. The general structureand the functional principle of OLEDs are known to the person skilled inthe art and are described, for example, in U.S. Pat. No. 4,539,507.

Further improvements are still necessary with respect to the performancedata of OLEDs, in particular with a view to broad commercial use, forexample in display devices or as light sources. Of particular importancein this connection are the lifetime, the efficiency and the operatingvoltage of the OLEDs and also the colour values achieved. In particular,in case of blue-emitting OLEDs, there is potential for improvement withrespect to the lifetime, the efficiency of the devices and the colourpurity of the emitters.

An important starting point for achieving the said improvements is thechoice of the emitter compound and of the host compound employed in theelectronic device.

Blue-fluorescent emitters known from the prior art are a multiplicity ofcompounds. Arylamines containing one or more condensed aryl are knownfrom the prior art. Arylamines containing dibenzofuran groups (asdisclosed in US 2017/0012214) or indenodibenzofuran groups (as disclosedin CN 10753308) are also known from the prior art.

In the last decade, compounds which exhibit thermally activated delayedfluorescence (TADF) (e.g. H. Uoyama et al., Nature 2012, vol. 492, 234)have also been intensively researched. TADF materials are, in general,organic materials in which the energy gap between the lowest tripletstate T₁ and the first excited singlet state S₁ is sufficiently small sothat the S₁ state is thermally accessible from the T₁ state. Forquantum-statistical reasons, on electronic excitation in the OLED, 75%of the excited states are in the triplet state and 25% in the singletstate. Since purely organic molecules cannot usually emit efficientlyfrom the triplet state, 75% of the excited states cannot be utilized foremission, which means that it is possible in principle to convert only25% of the excitation energy to light. If, however, the energy gapbetween the lowest triplet state and the lowest excited singlet state issufficiently small, the first excited singlet state of the molecule isaccessible from the triplet state by thermal excitation and can bepopulated thermally. Since this singlet state is an emissive state fromwhich fluorescence is possible, this state can be used to generatelight. Thus, in principle, the conversion of up to 100% of theelectrical energy to light is possible when purely organic materials areused as emitter.

Recently, polycyclic aromatic compounds comprising Boron and Nitrogenatoms have been described (for example in US2015/0236274A1,CN107501311A, WO2018/047639A1). These compounds can be used asfluorescent emitters, where the fluorescent emission is mainly promptfluorescence or as TADF compounds.

However, there is still a need for further fluorescent emitters,especially blue-fluorescent emitters, which may be employed in OLEDs andlead to OLEDs having very good properties in terms of lifetime, colouremission and efficiency. More particularly, there is a need forblue-fluorescent emitters combining very high efficiencies, very goodlife time and suitable colour coordinates as well as high colour purity.

Recently, organic electroluminescent devices having, in the emittinglayer, a TADF compound as a sensitizer and a fluorescent compound havinghigh steric shielding with respect to its environment as an emitter havebeen described (for example in WO2015/135624). This device constructionmakes it possible to provide organic electroluminescent devices whichemit in all emission colours, so that it is possible to use the basestructures of known fluorescent emitters which nevertheless exhibit thehigh efficiency of electroluminescent devices with TADF. This is alsoknown as hyperfluorescence.

As an alternative, the prior art describes organic electroluminescentdevices comprising, in the emitting layer, a phosphorescentorganometallic complex as a sensitizer, which shows mixing of S1 and T1states due to the large spin-orbit coupling, and a fluorescent compoundas an emitter, so that the emission decay time can significantly beshortened. This is also known as hyperphosphorescence.

Hyperfluorescence and hyperphosphorescence are also promising techniquesto improve OLEDs properties, especially in terms of deep blue emission.

However, here too, further improvements are still necessary with respectto the performance data of OLEDs, in particular with a view to broadcommercial use, for example in display devices or as light sources. Ofparticular importance in this connection are the lifetime, theefficiency, the operating voltage of the OLEDs and the colour valuesachieved, in particular colour purity.

An important starting point for achieving the said improvements inhyperfluorescent and hyperphosphorescent systems is the choice of thesterically hindered fluorescent emitter compound.

In WO 2015/135624, sterically hindered fluorescent emitters based onrubrene are described. However, there is still a need for furthersterically hindered fluorescent emitters, especially sterically hinderedblue-fluorescent emitters, which lead to OLEDs having very goodproperties in terms of efficiency and colour emission. Moreparticularly, there is a need for deep blue-fluorescent emitterscombining very high efficiency, very good life time and suitable colourcoordinates as well as high colour purity.

Furthermore, it is known that an OLED may comprise different layers,which may be applied either by vapour deposition in a vacuum chamber orby processing from a solution. The processes based on vapour depositionlead to good results, but such processes are complex and expensive.Therefore, there is also a need for OLED materials that can be easilyand reliably processed from solution. In this case, the materials shouldhave good solubility properties in the solution that comprises them.Additionally, the OLED materials that are processed from a solutionshould be able to orientate themselves in the deposited film to improvethe overall efficiency of the OLED. The term orientation means here thehorizontal molecular orientation of the compounds, as explained in Zhaoet al., Horizontal molecular orientation in solution-processed organiclight-emitting diodes, Appl. Phys. Lett.

Thus, the present invention is based on the technical object ofproviding emitters exhibiting prompt fluorescence and/or delayedfluorescence. The present invention is also based on the technicalobject of providing sterically hindered fluorescent emitters, which canbe used in combination with a sensitizer compound in a hyperfluorescentor hyperphosphorescent system.

The present invention is also based on the technical object of providingcompounds which are suitable for use in electronic devices, such asOLEDs, more particularly as emitters and, which are suitable for vacuumprocessing or for solution processing.

In investigations on novel compounds for use in electronic devices, ithas now been found, that compounds of formula (1) as defined below areeminently suitable for use in electronic devices. In particular, theyachieve one or more, preferably all, of the above-mentioned technicalobjects.

The invention thus relates to compounds of the formula (1),

where the following applies to the symbols and indices used:

-   X¹ stands, on each occurrence, identically or differently, for CR¹    or N;-   X² stands, on each occurrence, identically or differently, for CR²    or N;-   X^(A) stands, on each occurrence, identically or differently, for    CR^(A) or N;-   Y is a single bond or a divalent bridge selected from —C(R^(Y))₂—,    —C(R^(Y))₂—C(R^(Y))₂—, —O—, —S—, —S(═O)₂— and —C(═O)—;-   R^(B) stands on each occurrence, identically or differently, for CN,    N(Ar)₂, C(═O)Ar, P(═O)(Ar)₂, S(═O)Ar, S(═O)₂Ar, N(R)₂, Si(R)_(3,2),    OSO₂R, a straight-chain alkyl, alkoxy or thioalkoxy group having 1    to 40 carbon atoms or an alkenyl or alkynyl group having 2 to 40    carbon atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy    group having 3 to 40 carbon atoms, each of which may be substituted    by one or more radicals R, where in each case one or more    non-adjacent CH₂ groups may be replaced by RC═CR, C≡C, Si(R)₂,    Ge(R)₂, Sn(R)₂, C═O, C═S, C═Se, P(═O)(R), SO, SO₂, O, S or CONR and    where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or    NO₂, or an aromatic or heteroaromatic ring system having 5 to 60    aromatic ring atoms, which may in each case be substituted by one or    more radicals R, or an aryloxy group having 5 to 60 aromatic ring    atoms, which may be substituted by one or more radicals R, or an    aralkyl or heteroaralkyl group which has 5 to 60 aromatic ring    atoms, which may be substituted by one or more R radicals;-   R^(Y) stands on each occurrence, identically or differently, for H,    D, F, Cl, Br, I, CHO, CN, N(Ar)₂, C(═O)Ar, P(═O)(Ar)₂, S(═O)Ar,    S(═O)₂Ar, NO₂, N(R)₂, Si(R)₃, B(OR)₂, OSO₂R, a straight-chain alkyl,    alkoxy or thioalkoxy group having 1 to 40 carbon atoms or an alkenyl    or alkynyl group having 2 to 40 carbon atoms or a branched or cyclic    alkyl, alkoxy or thioalkoxy group having 3 to 40 carbon atoms, each    of which may be substituted by one or more radicals R, where in each    case one or more non-adjacent CH₂ groups may be replaced by RC═CR,    C≡C, Si(R)₂, Ge(R)₂, Sn(R)₂, C═O, C═S, C═Se, P(═O)(R), SO, SO₂, O, S    or CONR and where one or more H atoms may be replaced by D, F, Cl,    Br, I, CN or NO₂, or an aromatic or heteroaromatic ring system    having 5 to 60 aromatic ring atoms, which may in each case be    substituted by one or more radicals R, or an aryloxy group having 5    to 60 aromatic ring atoms, which may be substituted by one or more    radicals R, or an aralkyl or heteroaralkyl group which has 5 to 60    aromatic ring atoms, which may be substituted by one or more R    radicals; where two adjacent substituents R^(Y) may form a mono- or    polycyclic, aliphatic ring system or aromatic ring system, which may    be substituted by one or more radicals R′;-   R¹, R², R^(A) stand on each occurrence, identically or differently,    for H, D, F, Cl, Br, I, CHO, CN, N(Ar)₂, C(═O)Ar, P(═O)(Ar)₂,    S(═O)Ar, S(═O)₂Ar, NO₂, Si(R)₃, B(OR)₂, OSO₂R, a straight-chain    alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or branched    or cyclic alkyl, alkoxy or thioalkyl groups having 3 to 40 C atoms,    each of which may be substituted by one or more radicals R, where in    each case one or more non-adjacent CH₂ groups may be replaced by    RC═CR, C≡C, Si(R)₂, Ge(R)₂, Sn(R)₂, C═O, C═S, C═Se, P(═O)(R), SO,    SO₂, O, S or CONR and where one or more H atoms may be replaced by    D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring    system having 5 to 60 aromatic ring atoms, which may in each case be    substituted by one or more radicals R, an aryloxy group having 5 to    60 aromatic ring atoms, which may be substituted by one or more    radicals R, or an aralkyl or heteroaralkyl group which has 5 to 60    aromatic ring atoms, which may be substituted by one or more R    radicals; where two adjacent radicals selected from R¹, R², R^(A)    may form a mono- or polycyclic, aliphatic ring system or aromatic    ring system, which may be substituted by one or more radicals R;-   R stands on each occurrence, identically or differently, for H, D,    F, Cl, Br, I, CHO, CN, N(Ar)₂, C(═O)Ar, P(═O)(Ar)₂, S(═O)Ar,    S(═O)₂Ar, NO₂, Si(R′)₃, B(OR′)₂, OSO₂R′, a straight-chain alkyl,    alkoxy or thioalkyl group having 1 to 40 C atoms or branched or    cyclic alkyl, alkoxy or thioalkyl groups having 3 to 40 C atoms,    each of which may be substituted by one or more radicals R′, where    in each case one or more non-adjacent CH₂ groups may be replaced by    R′C═CR′, C≡C, Si(R′)₂, Ge(R′)₂, Sn(R′)₂, C═O, C═S, C═Se, P(═O)(R′),    SO, SO₂, O, S or CONR′ and where one or more H atoms may be replaced    by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring    system having 5 to 60 aromatic ring atoms, which may in each case be    substituted by one or more radicals R′, or an aryloxy group having 5    to 60 aromatic ring atoms, which may be substituted by one or more    radicals R′, where two adjacent radicals R may form a mono- or    polycyclic, aliphatic ring system or aromatic ring system, which may    be substituted by one or more radicals R′;-   Ar is on each occurrence, identically or differently, an aromatic or    heteroaromatic ring system having 5 to 24 aromatic ring atoms, which    may in each case also be substituted by one or more radicals R′;-   R′ stands on each occurrence, identically or differently, for H, D,    F, Cl, Br, I, CN, a straight-chain alkyl, alkoxy or thioalkyl group    having 1 to 20 C atoms or branched or cyclic alkyl, alkoxy or    thioalkyl group having 3 to 20 C atoms, where in each case one or    more non-adjacent CH₂ groups may be replaced by SO, So₂, O, S and    where one or more H atoms may be replaced by D, F, Cl, Br or I, or    an aromatic or heteroaromatic ring system having 5 to 24 C atoms.

Adjacent substituents in the sense of the present invention aresubstituents which are bonded to atoms which are linked directly to oneanother or which are bonded to the same atom.

Furthermore, the following definitions of chemical groups apply for thepurposes of the present application:

An aryl group in the sense of this invention contains 6 to 60 aromaticring atoms, preferably 6 to 40 aromatic ring atoms, more preferably 6 to20 aromatic ring atoms; a heteroaryl group in the sense of thisinvention contains 5 to 60 aromatic ring atoms, preferably 5 to 40aromatic ring atoms, more preferably 5 to 20 aromatic ring atoms, atleast one of which is a heteroatom. The heteroatoms are preferablyselected from N, O and S. This represents the basic definition. If otherpreferences are indicated in the description of the present invention,for example with respect to the number of aromatic ring atoms or theheteroatoms present, these apply.

An aryl group or heteroaryl group here is taken to mean either a simplearomatic ring, i.e. benzene, or a simple heteroaromatic ring, forexample pyridine, pyrimidine or thiophene, or a condensed (annellated)aromatic or heteroaromatic polycycle, for example naphthalene,phenanthrene, quinoline or carbazole. A condensed (annellated) aromaticor heteroaromatic polycycle in the sense of the present applicationconsists of two or more simple aromatic or heteroaromatic ringscondensed with one another.

An aryl or heteroaryl group, which may in each case be substituted bythe above-mentioned radicals and which may be linked to the aromatic orheteroaromatic ring system via any desired positions, is taken to mean,in particular, groups derived from benzene, naphthalene, anthracene,phenanthrene, pyrene, dihydropyrene, chrysene, perylene, fluoranthene,benzanthracene, benzophenanthrene, tetracene, pentacene, benzopyrene,furan, benzofuran, isobenzofuran, dibenzofuran, thiophene,benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole,isoindole, carbazole, pyridine, quinoline, isoquinoline, acridine,phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline,benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole,imidazole, benzimidazole, naphthimidazole, phenanthrimidazole,pyridimidazole, pyrazinimidazole, quinoxalinimidazole, oxazole,benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole,1,2-thiazole, 1,3-thiazole, benzothiazole, pyridazine, benzopyridazine,pyrimidine, benzopyrimidine, quinoxaline, pyrazine, phenazine,naphthyridine, azacarbazole, benzocarboline, phenanthroline,1,2,3-triazole, 1,2,4-triazole, benzotriazole, 1,2,3-oxadiazole,1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole,1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 1,3,5-triazine,1,2,4-triazine, 1,2,3-triazine, tetrazole, 1,2,4,5-tetrazine,1,2,3,4-tetrazine, 1,2,3,5-tetrazine, purine, pteridine, indolizine andbenzothiadiazole.

An aryloxy group in accordance with the definition of the presentinvention is taken to mean an aryl group, as defined above, which isbonded via an oxygen atom. An analogous definition applies toheteroaryloxy groups.

An aralkyl group in accordance with the definition of the presentinvention is taken to mean an alkyl group, where at least one hydrogenatom is replaced by an aryl group. An analogous definition applies toheteroaralkyl groups.

An aromatic ring system in the sense of this invention contains 6 to 60C atoms in the ring system, preferably 6 to 40 C atoms, more preferably6 to 20 C atoms. A heteroaromatic ring system in the sense of thisinvention contains 5 to 60 aromatic ring atoms, preferably 5 to 40aromatic ring atoms, more preferably 5 to 20 aromatic ring atoms, atleast one of which is a heteroatom.

The heteroatoms are preferably selected from N, O and/or S. An aromaticor heteroaromatic ring system in the sense of this invention is intendedto be taken to mean a system which does not necessarily contain onlyaryl or heteroaryl groups, but instead in which, in addition, aplurality of aryl or heteroaryl groups may be connected by anon-aromatic unit (preferably less than 10% of the atoms other than H),such as, for example, an sp³-hybridised C, Si, N or O atom, ansp²-hybridised C or N atom or an sp-hybridised C atom. Thus, forexample, systems such as 9,9′-spirobifluorene, 9,9′-diarylfluorene,triarylamine, diaryl ether, stilbene, etc., are also intended to betaken to be aromatic ring systems in the sense of this invention, as aresystems in which two or more aryl groups are connected, for example, bya linear or cyclic alkyl, alkenyl or alkynyl group or by a silyl group.Furthermore, systems in which two or more aryl or heteroaryl groups arelinked to one another via single bonds are also taken to be aromatic orheteroaromatic ring systems in the sense of this invention, such as, forexample, systems such as biphenyl, terphenyl or diphenyltriazine.

An aromatic or heteroaromatic ring system having 5-60 aromatic ringatoms, which may in each case also be substituted by radicals as definedabove and which may be linked to the aromatic or heteroaromatic groupvia any desired positions, is taken to mean, in particular, groupsderived from benzene, naphthalene, anthracene, benzanthracene,phenanthrene, benzophenanthrene, pyrene, chrysene, perylene,fluoranthene, naphthacene, pentacene, benzopyrene, biphenyl,biphenylene, terphenyl, terphenylene, quaterphenyl, fluorene,spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene,cis- or trans-indenofluorene, truxene, isotruxene, spirotruxene,spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran,thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole,indole, isoindole, carbazole, indolocarbazole, indenocarbazole,pyridine, quinoline, isoquinoline, acridine, phenanthridine,benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline,phenothiazine, phenoxazine, pyrazole, indazole, imidazole,benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole,pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole,naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1,2-thiazole,1,3-thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine,benzopyrimidine, quinoxaline, 1,5-diazaanthracene, 2,7-diazapyrene,2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene,4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine,phenothiazine, fluorubin, naphthyridine, azacarbazole, benzocarboline,phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole,1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole,1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole,1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine,tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine,purine, pteridine, indolizine and benzothiadiazole, or combinations ofthese groups.

For the purposes of the present invention, a straight-chain alkyl grouphaving 1 to 40 C atoms or a branched or cyclic alkyl group having 3 to40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, inwhich, in addition, individual H atoms or CH₂ groups may be substitutedby the groups mentioned above under the definition of the radicals, ispreferably taken to mean the radicals methyl, ethyl, n-propyl, i-propyl,n-butyl, i-butyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl,cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl,cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl,pentafluoroethyl, 2,2,2-trifluoroethyl, ethenyl, propenyl, butenyl,pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl,octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl oroctynyl. An alkoxy or thioalkyl group having 1 to 40 C atoms ispreferably taken to mean methoxy, trifluoromethoxy, ethoxy, n-propoxy,i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, n-pentoxy, s-pentoxy,2-methylbutoxy, n-hexoxy, cyclohexyloxy, n-heptoxy, cycloheptyloxy,n-octyloxy, cyclooctyloxy, 2-ethylhexyloxy, pentafluoroethoxy,2,2,2-trifluoroethoxy, methylthio, ethylthio, n-propylthio,i-propylthio, n-butylthio, i-butylthio, s-butylthio, t-butylthio,n-pentylthio, s-pentylthio, n-hexylthio, cyclohexylthio, n-heptylthio,cycloheptylthio, n-octylthio, cyclooctylthio, 2-ethylhexylthio,trifluoromethylthio, pentafluoroethylthio, 2,2,2-trifluoroethylthio,ethenylthio, propenylthio, butenylthio, pentenylthio, cyclopentenylthio,hexenylthio, cyclohexenylthio, heptenylthio, cycloheptenylthio,octenylthio, cyclooctenylthio, ethynylthio, propynylthio, butynylthio,pentynylthio, hexynylthio, heptynylthio or octynylthio.

The formulation that two or more radicals may form a ring with oneanother is, for the purposes of the present application, intended to betaken to mean, inter alia, that the two radicals are linked to oneanother by a chemical bond. This is illustrated by the followingschemes:

Furthermore, however, the above-mentioned formulation is also intendedto be taken to mean that, in the case where one of the two radicalsrepresents hydrogen, the second radical is bonded at the position towhich the hydrogen atom was bonded, with formation of a ring. This isillustrated by the following scheme:

Preferably, the group Y is a single bond or a divalent bridge selectedfrom —C(R^(Y))₂—, —O— or —S—. More preferably, the group Y is a singlebond or a group —C(R^(Y))₂—, even more preferably the group Y is asingle bond.

In accordance with a preferred embodiment, the group Y stands for asingle bond and the compounds of formula (1) correspond to compounds offormula (1-Y1),

where the symbols have the same meaning as above.

In accordance with another preferred embodiment, the group Y stands fora group —C(R^(Y))₂— and the compounds of formula (1) correspond tocompounds of formula (1-Y2),

Preferably, the group R^(Y) stands on each occurrence, identically ordifferently, for H, D, a straight-chain alkyl group having 1 to 20,preferably 1 to 10 carbon atoms or an alkenyl or alkynyl group having 2to 20, preferably 2 to 10 carbon atoms or a branched or cyclic alkylgroup having 3 to 20, preferably 3 to 10 carbon atoms, each of which maybe substituted by one or more radicals R, or an aromatic orheteroaromatic ring system having 5 to 60, preferably 5 to 40, morepreferably 5 to 30, very preferably 5 to 18 aromatic ring atoms, whichmay in each case be substituted by one or more radicals R; where twoadjacent substituents R^(Y) may form a mono- or polycyclic, aliphaticring system or aromatic ring system, which may be substituted by one ormore radicals R. In accordance with a preferred embodiment, two adjacentsubstituents R^(Y) form a ring of formula (R^(Y)-1),

where the group of formula (R^(Y)-1) may be substituted by one or moreradicals R and where the dashed bonds indicate the bonding to thestructure of formula (1).

If two adjacent substituents R^(Y) form a ring of formula (R^(Y)-1),then the compounds of formula (1) corresponds to compounds of formula(1-Y3),

where the symbols have the same meaning as above.

In accordance with a preferred embodiment, the compounds of formula (1)are selected from the compounds of formula (2),

where the symbols have the same meaning as above.

Preferably, the compounds of formula (2) correspond to compounds offormulae (2-Y1), (2-Y2) and (2-Y3),

In accordance with a very preferred embodiment, the compound thecompounds of formula (1) are selected from compounds of formula (3),

where the symbols have the same meaning as above.

Preferably, the compounds of formula (3) correspond to compounds offormulae (3-Y1), (3-Y2) and (3-Y3),

where the symbols have the same meaning as above.

In accordance with a particularly preferred embodiment, the compounds offormula (1) are selected from compounds of formula (4),

where the symbols have the same meaning as above.

Preferably, the compounds of formula (4) correspond to compounds offormulae (4-Y1), (4-Y2) and (4-Y3),

where the symbols have the same meaning as above.

Preferably, the group R^(B) stands on each occurrence, identically ordifferently, for a straight-chain alkyl, alkoxy or thioalkoxy grouphaving 1 to 40, preferably 1 to 20, more preferably 1 to 10 carbon atomsor an alkenyl or alkynyl group having 2 to 40, preferably 2 to 20, morepreferably 1 to 10 carbon atoms or a branched or cyclic alkyl, alkoxy orthioalkoxy group having 3 to 40, preferably 3 to 20, more preferably 3to 10 carbon atoms, each of which may be substituted by one or moreradicals R, where in each case one or more non-adjacent CH₂ groups maybe replaced by RC═CR, C≡C, Si(R)₂, Ge(R)₂, Sn(R)₂, C═O, C═S, C═Se,P(═O)(R), SO, SO₂, O, S or CONR and where one or more H atoms may bereplaced by D, F, Cl, Br, I, CN or NO₂, or an aromatic or heteroaromaticring system having 5 to 60, preferably 5 to 40, more preferably 5 to 30,very preferably 5 to 18 aromatic ring atoms, which may in each case besubstituted by one or more radicals R, or an aralkyl or heteroaralkylgroup which has 5 to 60, preferably 5 to 40, more preferably 5 to 30,very preferably 5 to 18 aromatic ring atoms, which may be substituted byone or more R radicals.

More preferably, the group R^(B) stands on each occurrence, identicallyor differently, for a straight-chain alkyl or alkoxy group having 1 to20, preferably 1 to 10 carbon atoms or an alkenyl or alkynyl grouphaving 2 to 20, preferably 2 to 10 carbon atoms or a branched or cyclicalkyl or alkoxy group having 3 to 20, preferably 3 to 10 carbon atoms,each of which may be substituted by one or more radicals R, where one ormore H atoms may be replaced by D, F, Cl or CN, or an aromatic ringsystem having 5 to 60, preferably 5 to 40, more preferably 5 to 30, verypreferably 5 to 18 aromatic ring atoms, which may in each case besubstituted by one or more radicals R, or an aralkyl or heteroaralkylgroup which has 5 to 60, preferably 5 to 40, more preferably 5 to 30,very preferably 5 to 18 aromatic ring atoms, which may be substituted byone or more R radicals.

Very preferably, the group R^(B) is selected on each occurrence,identically or differently, from branched or cyclic alkyl groupsrepresented by the general following formula (RS-a)

wherein

-   -   R²², R²³, R²⁴ are at each occurrence, identically or        differently, selected from H, a straight-chain alkyl group        having 1 to 10 carbon atoms, or a branched or cyclic alkyl group        having 3 to 10 carbon atoms, where the above-mentioned groups        may each be substituted by one or more radicals R²⁵, and where        two of radicals R²², R²³, R²⁴ or all radicals R²², R²³, R²⁴ may        be joined to form a (poly)cyclic alkyl group, which may be        substituted by one or more radicals R²⁵;    -   R²⁵ is at each occurrence, identically or differently, selected        from a straight-chain alkyl group having 1 to 10 carbon atoms,        or a branched or cyclic alkyl group having 3 to 10 carbon atoms;    -   with the proviso that at each occurrence at least one of        radicals R²², R²³ and R²⁴ is other than H, with the proviso that        at each occurrence all of radicals R²², R²³ and R²⁴ together        have at least 4 carbon atoms and with the proviso that at each        occurrence, if two of radicals R²², R²³, R²⁴ are H, the        remaining radical is not a straight-chain;        or from branched or cyclic alkoxy groups represented by the        general following formula (RS-b)

wherein

-   -   R²⁶, R²⁷, R²⁸ are at each occurrence, identically or        differently, selected from H, a straight-chain alkyl group        having 1 to 10 carbon atoms, or a branched or cyclic alkyl group        having 3 to 10 carbon atoms, where the above-mentioned groups        may each be substituted by one or more radicals R²⁵ as defined        above, and where two of radicals R²⁶, R²⁷, R²⁸ or all radicals        R²⁶, R²⁷, R²⁸ may be joined to form a (poly)cyclic alkyl group,        which may be substituted by one or more radicals R²⁵ as defined        above; with the proviso that at each occurrence only one of        radicals R²⁶, R²⁷ and R²⁸ may be H;        or from aralkyl groups represented by the general following        formula (RS-c)

wherein

-   -   R²⁹, R³⁰, R³¹ are at each occurrence, identically or        differently, selected from H, a straight-chain alkyl group        having 1 to 10 carbon atoms, or a branched or cyclic alkyl group        having 3 to 10 carbon atoms, where the above-mentioned groups        may each be substituted by one or more radicals R³², or an        aromatic ring system having 6 to 30 aromatic ring atoms, which        may in each case be substituted by one or more radicals R³², and        where two or all of radicals R²⁹, R³⁰, R³¹ may be joined to form        a (poly)cyclic alkyl group or an aromatic ring system, each of        which may be substituted by one or more radicals R³²;    -   R³² is at each occurrence, identically or differently, selected        from a straight-chain alkyl group having 1 to 10 carbon atoms,        or a branched or cyclic alkyl group having 3 to 10 carbon atoms,        or an aromatic ring system having 6 to 24 aromatic ring atoms;    -   with the proviso that at each occurrence at least one of        radicals R²⁹, R³⁰ and R³¹ is other than H and that at each        occurrence at least one of radicals R²⁹, R³⁰ and R³¹ is or        contains an aromatic ring system having at least 6 aromatic ring        atoms;        or from aromatic ring systems represented by the general        following formula (RS-d)

wherein

-   -   R⁴⁰ to R⁴⁴ is at each occurrence, identically or differently,        selected from H, a straight-chain alkyl group having 1 to 10        carbon atoms, or a branched or cyclic alkyl group having 3 to 10        carbon atoms, where the above-mentioned groups may each be        substituted by one or more radicals R³², or an aromatic ring        system having 6 to 30 aromatic ring atoms, which may in each        case be substituted by one or more radicals R³², and where two        or more of radicals R⁴⁰ to R⁴⁴ may be joined to form a        (poly)cyclic alkyl group or an aromatic ring system, each of        which may be substituted by one or more radicals R³² as defined        above.

Examples of suitable groups of formulae (RS-a) to (RS-d) are the groups(RS-1) to (RS-78):

where the dashed bond indicates the bonding of these groups to thestructure of formula (1) and where the groups of formulae (RS-1) to(RS-47) may further be substituted by a least one group R²⁵ as definedabove and groups (RS-48) to (RS-78) may further be substituted by aleast one group R³² as defined above.

Preferably, R² and R^(A) stand on each occurrence, identically ordifferently, for H, D, F, Cl, Br, I, CN, N(Ar)₂, a straight-chain alkyl,alkoxy or thioalkyl group having 1 to 40, preferably 1 to 20, morepreferably 1 to 10 C atoms or branched or cyclic alkyl, alkoxy orthioalkyl groups having 3 to 40, preferably 3 to 20, more preferably 3to 10 C atoms, each of which may be substituted by one or more radicalsR, where in each case one or more non-adjacent CH₂ groups may bereplaced by RC═CR, C≡C, Si(R)₂, Ge(R)₂, Sn(R)₂, C═O, C═S, C═Se,P(═O)(R), SO, SO₂, O, S or CONR and where one or more H atoms may bereplaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromaticring system having 5 to 60, preferably 1 to 40, more preferably 1 to 30,very preferably 1 to 18 aromatic ring atoms, which may in each case besubstituted by one or more radicals R, or an aralkyl or heteroaralkylgroup which has 5 to 60, preferably 1 to 40, more preferably 1 to 30,very preferably 1 to 18 aromatic ring atoms, which may be substituted byone or more R radicals.

More preferably, R² and R^(A) stand on each occurrence, identically ordifferently, for H, D, F, CN, a straight-chain alkyl, alkoxy orthioalkyl group having 1 to 40, preferably 1 to 20, more preferably 1 to10 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl groupshaving 3 to 40 preferably 3 to 20, more preferably 3 to 10 C atoms, eachof which may be substituted by one or more radicals R, where in eachcase one or more non-adjacent CH₂ groups may be replaced by RC═CR, C≡C,O or S and where one or more H atoms may be replaced by D, F, anaromatic or heteroaromatic ring system having 5 to 60, preferably 1 to40, more preferably 1 to 30, very preferably 1 to 18 aromatic ringatoms, which may in each case be substituted by one or more radicals Ror an aralkyl or heteroaralkyl group which has 5 to 60, preferably 1 to40, more preferably 1 to 30, very preferably 1 to 18 aromatic ringatoms, which may be substituted by one or more R radicals.

Very preferably, R² and R^(A) stand on each occurrence, identically ordifferently,

for H, D, F, CN; or

for a group of formula (RS-a), a group of formula (RS-b), a group offormula (RS-c) or a group of formula (RS-d), where the groups offormulae (RS-a), (RS-b), (RS-c) and (RS-d) have the same definition asin claim 6; orfor a group of formula (ArL-1),

where the dashed bond in formula (ArL-1) indicates the bonding to thestructure of formula (1), where Ar², Ar³ stand on each occurrence,identically or differently, for an aromatic or heteroaromatic ringsystems having 5 to 60 aromatic ring atoms, which may in each case besubstituted by one or more radicals R; and where m is an integerselected from 1 to 10.

In accordance with a preferred embodiment, at least one of the group R²or R^(A) stands for a group of formula (RS-a), a group of formula(RS-b), a group of formula (RS-c) or a group of formula (RS-d), wherethe groups of formulae (RS-a), (RS-b), (RS-c) and (RS-d) are as definedabove.

In accordance with a preferred embodiment, the groups R^(B) and R^(A)are on each occurrence, identically or differently, selected from thegroups of formulae (RS-a), (RS-b), (RS-c) and (RS-d), where the groupsof formulae (RS-a), (RS-b), (RS-c) and (RS-d) have the same definitionas above.

In accordance with a preferred embodiment, at least one of the group R,R² or R^(A) stands for a group of formula (ArL-1) as defined above.

Preferably, the index m in the group of formula (ArL-1) is an integerselected from 1 to 6, very preferably from 1 to 4.

In formula (ArL-1), it is preferred that the group Ar² is selected fromthe groups of formulae (Ar2-1) to (Ar2-25),

where the dashed bonds indicate the bonding to the structure of formula(1) and to a group Ar² or Ar³ and the groups of formulae (Ar2-1) to(Ar2-25) may be substituted at each free position by a group R, whichhas the same meaning as above and where:

-   E⁴ is selected from —B(R⁰⁻), —C(R⁰)₂—, —C(R⁰)₂—C(R⁰)₂—, —Si(R⁰)₂—,    —C(═O)—, —C(═NR⁰)—, —C═(C(R⁰))₂—, —O—, —S—, —S(═O)—, —SO₂—, —N(R⁰)—,    —P(R⁰)— and —P((═O)R⁰)—;-   R⁰ stands on each occurrence, identically or differently, for H, D,    F, CN, a straight-chain alkyl group having 1 to 40 C atoms or    branched or cyclic alkyl group having 3 to 40 C atoms, each of which    may be substituted by one or more radicals R, where in each case one    or more non-adjacent CH₂ groups may be replaced by RC═CR, C≡C, C═O,    C═S, SO, SO₂, O or S and where one or more H atoms may be replaced    by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring    system having 5 to 60 aromatic ring atoms, which may in each case be    substituted by one or more radicals R; where two adjacent    substituents R⁰ may form a mono- or polycyclic, aliphatic ring    system or aromatic ring system, which may be substituted by one or    more radicals R, which has the same meaning as above.

Preferably, E⁴ is selected from —C(R⁰)₂—, —Si(R⁰)₂—, —O—, —S— or—N(R⁰)—, where the substituent R⁰ has the same meaning as above.

Preferably, R⁰ stands on each occurrence, identically or differently,for H, D, F, CN, a straight-chain alkyl group having 1 to 40, preferably1 to 20, more preferably 1 to 10 C atoms or branched or cyclic alkylgroup having 3 to 40, preferably 3 to 20, more preferably 3 to 10 Catoms, each of which may be substituted by one or more radicals R, anaromatic or heteroaromatic ring system having 5 to 60, preferably 5 to40, more preferably 5 to 30, very preferably 5 to 18 aromatic ringatoms, which may in each case be substituted by one or more radicals R;where two adjacent substituents R⁰ may form a mono- or polycyclic,aliphatic ring system or aromatic ring system, which may be substitutedby one or more radicals R, which has the same meaning as above. Examplesof suitable groups R⁰ are H, methyl, ethyl, propyl, butyl, substitutedand unsubstituted phenyl, substituted and unsubstituted biphenyl,substituted and unsubstituted naphthyl and substituted and unsubstitutedfluorene.

Among formulae (Ar2-1) to (Ar2-25), following formulae are preferred:

(Ar2-1), (Ar2-2), (Ar2-3), (Ar2-18), (Ar2-19), (Ar2-20), (Ar2-21),(Ar2-22) and (Ar2-25).

Furthermore, in formula (ArL-1), it is preferred that Ar³ is on eachoccurrence, identically or differently, selected from the groupconsisting of the groups of formulae (Ar3-1) to (Ar3-27),

where the dashed bond indicates the bonding to Ar² and where E⁴ has thesame meaning as above and the groups of formulae (Ar3-1) to (Ar3-27) maybe substituted at each free position by a group R, which has the samemeaning as above.

Among formulae (Ar3-1) to (Ar2-27), following formulae are preferred:

(Ar3-1), (Ar3-2), (Ar3-23), (Ar3-24), (Ar3-25) and (Ar3-27).

In accordance with a preferred embodiment at least one group Ar² standsfor a group of formula (Ar2-2) and/or at least one group Ar³ stands fora group of formula (Ar3-2),

wherethe dashed bonds in formula (Ar2-2) indicate the bonding to thestructure of formula (1) and to a group Ar² or Ar³; and the dashed bondin formula (Ar3-2) indicates the bonding to Ar²; and E⁴ has the samemeaning as in above; and the groups of formulae (Ar2-2) and (Ar3-2) maybe substituted at each free position by a group R, which has the samemeaning as above.

In accordance with a very preferred embodiment, at least one group Ar²stands for a group of formula (Ar2-2-1) and/or at least one group Ar³stands for a group of formula (Ar3-2-1),

wherethe dashed bonds in formula (Ar2-2-1) indicate the bonding to thestructure of formula (1) and to a group Ar² or Ar³;the dashed bond in formula (Ar3-2-1) indicates the bonding to Ar²;E⁴ has the same meaning as above; andthe groups of formulae (Ar2-2-1) and (Ar3-2-1) may be substituted ateach free position by a group R, which has the same meaning as above.

In accordance with a particularly preferred embodiment, at least onegroup Ar² stands for a group of formula (Ar2-2-1b) and/or at least onegroup Ar³ stands for a group of formula (Ar3-2-1 b),

wherethe dashed bonds in formula (Ar2-2-1 b) indicate the bonding to thestructure of formula (1) and to a group Ar² or Ar³;the dashed bond in formula (Ar3-2-1 b) indicates the bonding to Ar²; R⁰has the same meaning as above; andthe groups of formulae (Ar2-2-1 b) and (Ar3-2-1 b) may be substituted ateach free position by a group R, which has the same meaning as above.

Examples of very suitable groups R² and R^(A) are H, D, F, CN,substituted and unsubstituted straight-chain alkyl groups having 1 to 10C atoms, more particularly, methyl, ethyl, propyl, butyl, substitutedand unsubstituted branched or cyclic alkyl group having 3 to 10 C atoms,more particularly t-butyl, and aromatic or heteroaromatic ring systemsselected from the groups of formulae (Ar1-1) to (Ar1-24),

where in formulae (Ar1-1) to (Ar1-24):

-   -   the dashed bond indicates the bonding to the structure of        formula (1);    -   R^(N) in formula (Ar1-14) stands on each occurrence, identically        or differently, for H, D, a straight-chain alkyl group having 1        to 40, preferably 1 to 20, more preferably 1 to 10 C atoms or        branched or cyclic alkyl group having 3 to 40, preferably 3 to        20, more preferably 3 to 10 C atoms, each of which may be        substituted by one or more radicals R, where in each case one or        more non-adjacent CH₂ groups may be replaced by RC═CR, C≡C, C═O,        C═S, SO, So₂, O or S, and where one or more H atoms may be        replaced by D, F or CN, an aromatic or heteroaromatic ring        system having 5 to 60, preferably 5 to 40, more preferably 5 to        30, particularly preferably 5 to 18 aromatic ring atoms, which        may in each case be substituted by one or more radicals R, where        two adjacent substituents R^(N) may form a mono- or polycyclic,        aliphatic ring system or aromatic ring system, which may be        substituted by one or more radicals R, where R has the same        meaning as in claim 1;    -   R⁰ in formulae (Ar1-12) and (Ar1-21) to (Ar1-24) stands on each        occurrence, identically or differently, for H, D, F, CN, a        straight-chain alkyl group having 1 to 40 C atoms or branched or        cyclic alkyl group having 3 to 40 C atoms, each of which may be        substituted by one or more radicals R, where in each case one or        more non-adjacent CH₂ groups may be replaced by RC═CR, C≡C, C═O,        C═S, SO, So₂, O or S and where one or more H atoms may be        replaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or        heteroaromatic ring system having 5 to 60 aromatic ring atoms,        which may in each case be substituted by one or more radicals R;        where two adjacent substituents R⁰ may form a mono- or        polycyclic, aliphatic ring system or aromatic ring system, which        may be substituted by one or more radicals R, which has the same        meaning as above;    -   the groups of formulae (Ar1-1) to (Ar1-24) may be substituted at        each free position by a group R, which has the same meaning as        above.

In accordance with a particularly preferred embodiment, the compounds offormula (1) are selected from the compounds of formula (5),

where:

-   -   R⁴⁰, R⁴², R⁴⁴ are at each occurrence, identically or        differently, selected from H, a straight-chain alkyl group        having 1 to 10 carbon atoms, or a branched or cyclic alkyl group        having 3 to 10 carbon atoms, where the above-mentioned groups        may each be substituted by one or more radicals R³², or an        aromatic ring system having 6 to 30 aromatic ring atoms, which        may in each case be substituted by one or more radicals R³²;        where R³² is as defined above;    -   with the proviso that at least one of R⁴⁰, R⁴², R⁴⁴ is other        than H; and the other symbols have the same meaning as above.

Preferably, the compounds of formula (5) correspond to compounds offormulae (5-Y1), (5-Y2) and (5-Y3),

where the symbols have the same meaning as above.

In accordance with another particularly preferred embodiment, thecompounds of formula (1) are selected from the compounds of formula (6),

where:

-   -   R⁴¹, R⁴³ are at each occurrence, identically or differently,        selected from H, a straight-chain alkyl group having 1 to 10        carbon atoms, or a branched or cyclic alkyl group having 3 to 10        carbon atoms, where the above-mentioned groups may each be        substituted by one or more radicals R³², or an aromatic ring        system having 6 to 30 aromatic ring atoms, which may in each        case be substituted by one or more radicals R³²; where R³² is as        defined above;    -   with the proviso that at least one of R⁴¹, R⁴³ is other than H.

Preferably, the compounds of formula (6) correspond to compounds offormulae (6-Y1), (6-Y2) and (6-Y3),

where the symbols have the same meaning as above.

Preferably, the group R⁴² is at each occurrence, identically ordifferently, selected from H, a straight-chain alkyl group having 1 to10 carbon atoms, or a branched or cyclic alkyl group having 3 to 10carbon atoms, where the above-mentioned groups may each be substitutedby one or more radicals R32, or an aromatic ring system having 6 to 30aromatic ring atoms, which may in each case be substituted by one ormore radicals R³², and the groups R⁴⁰, R⁴⁴ are at each occurrence,identically or differently, selected from an aromatic ring system having6 to 30 aromatic ring atoms, which may in each case be substituted byone or more radicals R³².

In accordance with a preferred embodiment, the groups R⁴⁰, R⁴², R⁴⁴ informulae (5), (5-Y1), (5-Y2) and (5-Y3) are at each occurrence,identically or differently, selected from a straight-chain alkyl grouphaving 1 to 10 carbon atoms, or a branched or cyclic alkyl group having3 to 10 carbon atoms, where the above-mentioned groups may each besubstituted by one or more radicals R³². More preferably, the groupsR⁴⁰, R⁴², R⁴⁴ are at each occurrence, identically or differently,selected from a straight-chain alkyl group having 1 to 10, preferably 1to 5 more preferably 1 to 3 carbon atoms, where the above-mentionedgroups may each be substituted by one or more radicals R³². Example ofsuitable groups R⁴⁰, R⁴², R⁴⁴ in this case are methyl, ethyl and butyl.

In accordance with another preferred embodiment, the groups R⁴⁰, R⁴²,R⁴⁴ are at each occurrence, identically or differently, selected from anaromatic ring system having 6 to 30 aromatic ring atoms, which may ineach case be substituted by one or more radicals R³². Preferably, thecompounds of formulae (1) are selected from the compounds of formulae(5-1), (5-2) and (5-3),

wherein each of formulae (5-1), (5-2) and (5-3) the phenyl groups indicatedwith —R³² are unsubstituted or substituted with one or more radicalsR³²;R⁴² and R⁴⁴ are at each occurrence, identically or differently, selectedfrom H, a straight-chain alkyl group having 1 to 10 carbon atoms, or abranched or cyclic alkyl group having 3 to 10 carbon atoms, where theabove-mentioned groups may each be substituted by one or more radicalsR³²; where R³² is as defined above.

More preferably, the compounds of formulae (5-1), (5-2) and (5-3)correspond to compounds of formulae (5-1-Y1) to (5-1-Y7), (5-2-Y1) to(5-2-Y7) and (5-3-Y1) to (5-3-Y7),

where in each of formulae (5-1-Y1) to (5-3-Y7), the phenyl groupsindicated with —R³² are unsubstituted or substituted with one or moreradicals R³² and where the symbols have the same meaning as above.

Preferably, the group R stands on each occurrence, identically ordifferently, for H, D, F, Cl, Br, I, CHO, CN, N(Ar)₂, si(R′)₃, astraight-chain alkyl, alkoxy or thioalkyl group having 1 to 40,preferably 1 to 20, more preferably 1 to 10 C atoms or branched orcyclic alkyl, alkoxy or thioalkyl groups having 3 to 40, preferably 3 to20, more preferably 3 to 10 C atoms, each of which may be substituted byone or more radicals R′, where in each case one or more non-adjacent CH₂groups may be replaced by R′C═CR′, O or S and where one or more H atomsmay be replaced by D, F or CN, an aromatic or heteroaromatic ring systemhaving 5 to 60 aromatic ring atoms, which may in each case besubstituted by one or more radicals R′, or an aryloxy group having 5 to60, preferably 5 to 40, more preferably 5 to 30, very preferably 5 to 18aromatic ring atoms, which may be substituted by one or more radicalsR′, where two adjacent radicals R may form a mono- or polycyclic,aliphatic ring system or aromatic ring system, which may be substitutedby one or more radicals R′. When R is selected from aromatic andheteroaromatic ring systems, it is preferably selected from aromatic andheteroaromatic ring systems having 5 to 40, preferably 5 to 30, morepreferably 5 to 18 aromatic ring atoms or from aromatic orheteroaromatic ring system having 5 to 60 aromatic ring atomscorresponding to groups of formula (ArL-1) as defined above.

Preferably, the group Ar is on each occurrence, identically ordifferently, an aromatic or heteroaromatic ring system having 5 to 18,preferably 6 to 18 aromatic ring atoms, which may in each case also besubstituted by one or more radicals R′.

Preferably, R stands on each occurrence, identically or differently, forH, D, F, Cl, Br, I, CN, a straight-chain alkyl, alkoxy or thioalkylgroup having 1 to 10 C atoms or branched or cyclic alkyl, alkoxy orthioalkyl group having 3 to 10 C atoms, where one or more H atoms may bereplaced by D or F, or an aromatic or heteroaromatic ring system having5 to 18, preferably 6 to 18 C atoms.

The following compounds are examples of compounds of formula (1):

The compounds according to the invention can be prepared by synthesissteps known to the person skilled in the art, such as, for example,bromination, Suzuki coupling, Ullmann coupling, Hartwig-Buchwaldcoupling, etc. An example of a suitable synthesis process is depicted ingeneral terms in schemes 1 and 2 below.

where X¹ and X² are a leaving groups preferably selected from halogens.X¹ is preferably selected from Br, Cl, I, more preferably Br, X² ispreferably selected from Br and Cl, more preferably Cl,where two radicals R present in the same boronic acid or ester group canbe bonded to each other and form a ring, where the symbols Y and R^(B)have the same meaning as above and where the compounds depicted inScheme 1 may be further substituted by radicals R¹, R² and R^(A) asdefined above.

where X¹ is a leaving group preferably selected from halogens like F,Br, Cl, I, preferably Br, where the symbols Y and R^(B) have the samemeaning as above, and where the compounds depicted in Scheme 2 may befurther substituted by radicals R¹, R² and R^(A) as defined above.

The present invention therefore relates to a process for the synthesisof the compounds according to the invention, comprising a step where atriarylamine is substituted by at least one boronic acid or ester group,where a cyclisation reaction occurs so that a boronic acid or estergroup forms a 6-membered ring with the adjacent aromatic orheteroaromatic groups present in the triarylamine (Scheme 1).

Especially a process such as mentioned before and comprising anadditional step, in which the boronic acid or ester group is reactedinto the chlorine substituted cyclisation product, using e.g. AlCl₃ asreactant. This intermediate is subsequently reacted with a metal organylreactant, e.g. a Grignard compound or a lithium organyl, whichsubstitutes the chlorine and the final 6-membered ring is obtainedcomprising a third aromatic substituent not being linked to the planartriarylamine core structure.

Therefore, the present invention relates also to a process for thepreparation of a compound according to one or more of the precedingclaims, characterized in that it comprises the following steps:

(i) cyclisation reaction of a triarylamine compound substituted by atleast one boronic acid or ester group, in the presence of a halidecompound, so that the boron atom of the boronic acid or ester groupforms a six-membered ring with an adjacent aromatic or heteroaromaticgroup present in the triarylamine and where the boron atom is furthersubstituted by a halogen;(ii) substitution reaction between the halogenated boron compoundobtained in step (i) and a metal organyl reactant so that the halogengroup on the boron atom is replaced by an organic group.

The present invention therefore also relates to a process for thesynthesis of the compounds according to the invention, comprising a stepwhere a triarylamine is substituted by at least two boron-halogencompounds, where a cyclisation reaction occurs so that a boron-halogencompound forms a 6-membered ring with the adjacent aromatic orheteroaromatic groups present in the triarylamine (Scheme 2).

For the processing of the compounds according to the invention from theliquid phase, for example by spin coating or by printing processes,formulations of the compounds according to the invention are necessary.These formulations can be, for example, solutions, dispersions oremulsions. It may be preferred to use mixtures of two or more solventsfor this purpose. Suitable and preferred solvents are, for example,toluene, anisole, o-, m- or p-xylene, methyl benzoate, mesitylene,tetralin, veratrol, THF, methyl-THF, THP, chlorobenzene, dioxane,phenoxytoluene, in particular 3-phenoxytoluene, (−)fenchone,1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene,1-methylnaphthalene, 2-methylbenzothiazole, 2-phenoxyethanol,2-pyrrolidinone, 3-methylanisole, 4-methylanisole, 3,4-dimethylanisole,3,5-dimethylanisole, acetophenone, α-terpineol, benzothiazole, butylbenzoate, cumene, cyclohexanol, cyclohexanone, cyclohexylbenzene,decalin, dodecylbenzene, ethyl benzoate, indane, methyl benzoate, NMP,p-cymene, phenetole, 1,4-diisopropylbenzene, dibenzyl ether, diethyleneglycol butyl methyl ether, triethylene glycol butyl methyl ether,diethylene glycol dibutyl ether, triethylene glycol dimethyl ether,diethylene glycol monobutyl ether, tripropylene glycol dimethyl ether,tetraethylene glycol dimethyl ether, 2-isopropylnaphthalene,pentylbenzene, hexylbenzene, heptylbenzene, octylbenzene,1,1-bis(3,4-dimethylphenyl)ethane or mixtures of these solvents.

The present invention therefore furthermore relates to a formulationcomprising a compound according to the invention and at least onefurther compound. The further compound may be, for example, a solvent,in particular one of the above-mentioned solvents or a mixture of thesesolvents. However, the further compound may also be at least one furtherorganic or inorganic compound which is likewise employed in theelectronic device, for example an emitting compound, in particular aphosphorescent dopant, and/or a further matrix material. Suitableemitting compounds and further matrix materials are indicated below inconnection with the organic electroluminescent device. This furthercompound may also be polymeric.

The compounds and mixtures according to the invention are suitable foruse in an electronic device. An electronic device here is taken to meana device which comprises at least one layer which comprises at least oneorganic compound. However, the component here may also compriseinorganic materials or also layers built up entirely from inorganicmaterials.

The present invention therefore furthermore relates to the use of thecompounds or mixtures according to the invention in an electronicdevice, in particular in an organic electroluminescent device.

The present invention again furthermore relates to an electronic devicecomprising at least one of the compounds or mixtures according to theinvention mentioned above. The preferences stated above for the compoundalso apply to the electronic devices.

The electronic device is preferably selected from the group consistingof organic electroluminescent devices (OLEDs, PLEDs), organic integratedcircuits (O-ICs), organic field-effect transistors (O-FETs), organicthin-film transistors (O-TFTs), organic light-emitting transistors(O-LETs), organic solar cells (O-SCs), organic dye-sensitised solarcells, organic optical detectors, organic photoreceptors, organicfield-quench devices (O-FQDs), light-emitting electrochemical cells(LECs), organic laser diodes (O-lasers) and “organic plasmon emittingdevices” (D. M. Koller et al., Nature Photonics 2008, 1-4), preferablyorganic electroluminescent devices (OLEDs, PLEDs), in particularphosphorescent OLEDs.

The organic electroluminescent device comprises a cathode, an anode andat least one emitting layer. Apart from these layers, it may alsocomprise further layers, for example in each case one or morehole-injection layers, hole-transport layers, hole-blocking layers,electron-transport layers, electron-injection layers, exciton-blockinglayers, electron-blocking layers and/or charge-generation layers. It islikewise possible for interlayers, which have, for example, anexciton-blocking function, to be introduced between two emitting layers.However, it should be pointed out that each of these layers does notnecessarily have to be present. The organic electroluminescent devicehere may comprise one emitting layer or a plurality of emitting layers.If a plurality of emission layers are present, these preferably have intotal a plurality of emission maxima between 380 nm and 750 nm,resulting overall in white emission, i.e. various emitting compoundswhich are able to fluoresce or phosphoresce are used in the emittinglayers. Particular preference is given to systems having three emittinglayers, where the three layers exhibit blue, green and orange or redemission (for the basic structure see, for example, WO 2005/011013).These can be fluorescent or phosphorescent emission layers or hybridsystems, in which fluorescent and phosphorescent emission layers arecombined with one another.

The compound according to the invention in accordance with theembodiments indicated above can be employed in various layers, dependingon the precise structure and on the substitution.

Preference is given to an organic electroluminescent device comprising acompound of the formula (1) or in accordance with the preferredembodiments as fluorescent emitters or TADF (Thermally Activated DelayedFluorescence) emitters. More particularly, the compound of the formula(1) or in accordance with the preferred embodiments is preferablyemployed as a blue-fluorescent emitter showing prompt fluorescence or asa blue TADF emitter.

In accordance with another preferred embodiment of the invention, thecompound of formula (1) or in accordance with the preferred embodimentsis employed in a hyperfluorescent system, as described for example inWO2015/135624, comprising the compound of formula (1) as a fluorescentemitter and a sensitizer compound selected from thermally activateddelayed fluorescence compounds (TADF compounds), wherein the energy ofthe sensitizer is transferred to the fluorescent emitter via Försterresonance energy transfer.

In accordance with still another preferred embodiment of the invention,the compound of formula (1) or in accordance with the preferredembodiments is employed in a hyperphosphorescent system, as describedfor example in WO2001/08230A1, comprising the compound of formula (1) asa fluorescent emitter, and a sensitizer compound selected fromphosphorescent compounds, wherein the energy of the sensitizer istransferred to the fluorescent emitter via Förster resonance energytransfer.

The compounds of formula (1) can also be employed in anelectron-transport layer and/or in an electron-blocking orexciton-blocking layer and/or in a hole-transport layer, depending onthe precise substitution. The preferred embodiments indicated above alsoapply to the use of the materials in organic electronic devices.

The compound of formula (1) is particularly suitable for use as a blueemitter compound. The electronic device concerned may comprise a singleemitting layer comprising the compound according to the invention or itmay comprise two or more emitting layers. The further emitting layershere may comprise one or more compounds according to the invention oralternatively other compounds.

If the compound according to the invention is employed as a fluorescentemitter or TADF emitter in an emitting layer, it is preferably employedin combination with one or more matrix materials. A matrix material hereis taken to mean a material which is present in the emitting layer,preferably as the principal component, and which does not emit light onoperation of the device.

Preferably, the matrix compound has a glass transition temperature T_(G)of greater than 70° C., more preferably greater than 90° C., mostpreferably greater than 110° C.

The proportion of the emitting compound in the mixture of the emittinglayer is between 0.1 and 50.0%, preferably between 0.5 and 20.0%,particularly preferably between 1.0 and 10.0%. Correspondingly, theproportion of the matrix material or matrix materials is between 50.0and 99.9%, preferably between 80.0 and 99.5%, particularly preferablybetween 90.0 and 99.0%.

The specifications of the proportions in % are, for the purposes of thepresent application, taken to mean % by vol. if the compounds areapplied from the gas phase and % by weight if the compounds are appliedfrom solution.

If the compound of formula (1) or in accordance with the preferredembodiments is employed in an emitting layer as a fluorescent emitter(prompt fluorescence), then the preferred matrix materials for use incombination with the fluorescent emitter are selected from the classesof the oligoarylenes (for example 2,2′,7,7′-tetraphenylspirobifluorenein accordance with EP 676461 or dinaphthylanthracene), in particular theoligoarylenes containing condensed aromatic groups, theoligoarylenevinylenes (for example DPVBi or spiro-DPVBi in accordancewith EP 676461), the polypodal metal complexes (for example inaccordance with WO 2004/081017), the hole-conducting compounds (forexample in accordance with WO 2004/058911), the electron-conductingcompounds, in particular ketones, phosphine oxides, sulfoxides, etc.(for example in accordance with WO 2005/084081 and WO 2005/084082), theatropisomers (for example in accordance with WO 2006/048268), theboronic acid derivatives (for example in accordance with WO 2006/117052)or the benzanthracenes (for example in accordance with WO 2008/145239).Particularly preferred matrix materials are selected from the classes ofthe oligoarylenes, comprising naphthalene, anthracene, benzanthraceneand/or pyrene or atropisomers of these compounds, theoligoarylenevinylenes, the ketones, the phosphine oxides and thesulfoxides. Very particularly preferred matrix materials are selectedfrom the classes of the oligoarylenes, comprising anthracene,benzanthracene, benzophenanthrene and/or pyrene or atropisomers of thesecompounds. An oligoarylene in the sense of this invention is intended tobe taken to mean a compound in which at least three aryl or arylenegroups are bonded to one another.

Particularly preferred matrix materials for use in combination with thecompounds of the formula (1) employed as fluorescent emitters in theemitting layer are depicted in the following table:

If the compound according to the invention is employed as a fluorescentemitting compound in an emitting layer, it may be employed incombination with one or more other fluorescent emitting compounds.

Preferred fluorescent emitters, besides the compounds according to theinvention, are selected from the class of the arylamines. An arylaminein the sense of this invention is taken to mean a compound whichcontains three substituted or unsubstituted aromatic or heteroaromaticring systems bonded directly to the nitrogen. At least one of thesearomatic or heteroaromatic ring systems is preferably a condensed ringsystem, particularly preferably having at least 14 aromatic ring atoms.Preferred examples thereof are aromatic anthracenamines, aromaticanthracenediamines, aromatic pyrenamines, aromatic pyrenediamines,aromatic chrysenamines or aromatic chrysenediamines. An aromaticanthracenamine is taken to mean a compound in which one diarylaminogroup is bonded directly to an anthracene group, preferably in the9-position. An aromatic anthracenediamine is taken to mean a compound inwhich two diarylamino groups are bonded directly to an anthracene group,preferably in the 9,10-position. Aromatic pyrenamines, pyrenediamines,chrysenamines and chrysenediamines are defined analogously thereto,where the diarylamino groups are preferably bonded to the pyrene in the1-position or in the 1,6-position. Further preferred emitters areindenofluorenamines or indenofluorenediamines, for example in accordancewith WO 2006/108497 or WO 2006/122630, benzoindenofluorenamines orbenzoindenofluorenediamines, for example in accordance with WO2008/006449, and dibenzoindenofluorenamines ordibenzoindenofluorene-diamines, for example in accordance with WO2007/140847, and the indenofluorene derivatives containing condensedaryl groups which are disclosed in WO 2010/012328. Still furtherpreferred emitters are benzanthracene derivatives as disclosed in WO2015/158409, anthracene derivatives as disclosed in WO 2017/036573,fluorene dimers like in WO 2016/150544 or phenoxazine derivatives asdisclosed in WO 2017/028940 and WO 2017/028941. Preference is likewisegiven to the pyrenarylamines disclosed in WO 2012/048780 and WO2013/185871. Preference is likewise given to thebenzoindenofluorenamines disclosed in WO 2014/037077, thebenzofluorenamines disclosed in WO 2014/106522 and the indenofluorenesdisclosed in WO 2014/111269 or WO 2017/036574.

Examples of preferred fluorescent emitting compounds, besides thecompounds according to the invention, which can be used in combinationwith the compounds of the invention in an emitting layer or which can beused in another emitting layer of the same device are depicted in thefollowing table:

If the compound of formula (1) or in accordance with the preferredembodiments is employed in an emitting layer as a TADF emitter, then thepreferred matrix materials for use in combination with the TADF emitterare selected from the classes of the ketones, phosphine oxides,sulfoxides and sulfones, for example according to WO 2004/013080, WO2004/093207, WO 2006/005627 or WO 2010/006680, triarylamines, carbazolederivatives, e.g. CBP (N,N-biscarbazolylbiphenyl), m-CBP or thecarbazole derivatives disclosed in WO 2005/039246, US 2005/0069729, JP2004/288381, EP 1205527, WO 2008/086851 or US 2009/0134784, dibenzofuranderivatives, indolocarbazole derivatives, for example according to WO2007/063754 or WO 2008/056746, indenocarbazole derivatives, for exampleaccording to WO 2010/136109 or WO 2011/000455, azacarbazoles, forexample according to EP 1617710, EP 1617711, EP 1731584, JP 2005/347160,bipolar matrix materials, for example according to WO 2007/137725,silanes, for example according to WO 2005/111172, azaboroles or boronicesters, for example according to WO 2006/117052, diazasilolederivatives, for example according to WO 2010/054729, diazaphospholederivatives, for example according to WO 2010/054730, triazinederivatives, for example according to WO 2010/015306, WO 2007/063754 orWO 2008/056746, pyrimidine derivatives, quinoxaline derivatives, Zncomplexes, Al complexes or Be complexes, for example according to EP652273 or WO 2009/062578, or bridged carbazole derivatives, for exampleaccording to US 2009/0136779, WO 2010/050778, WO 2011/042107 or WO2011/088877. Suitable matrix materials are also those described in WO2015/135624. These are incorporated into the present invention byreference. It is also possible to use mixtures of two or more of thesematrix materials.

The matrix compounds for TADF emitters are preferablycharge-transporting, i.e. electron-transporting or hole-transporting, orbipolar compounds. Matrix compounds used may additionally also becompounds which are neither hole- nor electron-transporting in thecontext of the present application. An electron-transporting compound inthe context of the present invention is a compound having a LUMO ≤−2.50eV. Preferably, the LUMO is ≤−2.60 eV, more preferably ≤−2.65 eV, mostpreferably ≤−2.70 eV. The LUMO is the lowest unoccupied molecularorbital. The value of the LUMO of the compound is determined byquantum-chemical calculation, as described in general terms in theexamples section at the back. A hole-transporting compound in thecontext of the present invention is a compound having a HOMO ≥−5.5 eV.The HOMO is preferably ≥−5.4 eV, more preferably ≥−5.3 eV. The HOMO isthe highest occupied molecular orbital. The value of the HOMO of thecompound is determined by quantum-chemical calculation, as described ingeneral terms in the examples section at the back. A bipolar compound inthe context of the present invention is a compound which is both hole-and electron-transporting.

Suitable electron-conducting matrix compounds for TADF emitters areselected from the substance classes of the triazines, the pyrimidines,the lactams, the metal complexes, especially the Be, Zn and Alcomplexes, the aromatic ketones, the aromatic phosphine oxides, theazaphospholes, the azaboroles substituted by at least oneelectron-conducting substituent, and the quinoxalines. In a preferredembodiment of the invention, the electron-conducting compound is apurely organic compound, i.e. a compound containing no metals.

Furthermore, the hyperfluorescent and hyperphosphorescent systems asmentioned above preferably comprise, additionally to the sensitizer andthe fluorescent emitter, at least one matrix material. In this case, itis preferable that the lowest triplet energy of the matrix compound isnot more than 0.1 eV lower than the triplet energy of the sensitizercompound.

Especially preferably, T₁(matrix)≥T₁(sensitizer).

More preferably: T₁(matrix)−T₁(sensitizer) 0.1 eV,

most preferably: T₁(matrix)−T₁(sensitizer) 0.2 eV.

T₁(matrix) here is the lowest triplet energy of the matrix compound andT₁(sensitizer) is the lowest triplet energy of the sensitizer compound.The triplet energy of the matrix compound T₁(matrix) is determined herefrom the edge of the photoluminescence spectrum measured at 4 K of theneat film. T₁(sensitizer) is determined from the edge of thephotoluminescence spectrum measured at room temperature in toluenesolution.

Suitable matrix materials for hyperfluorescent or hyperphosphorescentsystems are the same matrix materials as mentioned above, more preferredare the matrix materials that are also preferred for TADF materials.

Suitable phosphorescent emitters are, in particular, compounds whichemit light, preferably in the visible region, on suitable excitation andin addition contain at least one atom having an atomic number greaterthan 20, preferably greater than 38 and less than 84, particularlypreferably greater than 56 and less than 80. The phosphorescent emittersused are preferably compounds which contain copper, molybdenum,tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium,platinum, silver, gold or europium, in particular compounds whichcontain iridium, platinum or copper.

For the purposes of the present invention, all luminescent iridium,platinum or copper complexes are regarded as phosphorescent compounds.

Examples of the phosphorescent emitters described above are revealed bythe applications WO 2000/70655, WO 2001/41512, WO 2002/02714, WO2002/15645, EP 1191613, EP 1191612, EP 1191614, WO 2005/033244, WO2005/019373 and US 2005/0258742. In general, all phosphorescentcomplexes as used in accordance with the prior art for phosphorescentOLEDs and as are known to the person skilled in the art in the area oforganic electroluminescent devices are suitable for use in the devicesaccording to the invention. The person skilled in the art will also beable to employ further phosphorescent complexes without inventive stepin combination with the compounds according to the invention in OLEDs.

Preferred matrix materials for phosphorescent emitters are aromaticketones, aromatic phosphine oxides or aromatic sulfoxides or sulfones,for example in accordance with WO 2004/013080, WO 2004/093207, WO2006/005627 or WO 2010/006680, triarylamines, carbazole derivatives, forexample CBP (N,N-biscarbazolylbiphenyl) or the carbazole derivativesdisclosed in WO 2005/039246, US 2005/0069729, JP 2004/288381, EP 1205527or WO 2008/086851, indolocarbazole derivatives, for example inaccordance with WO 2007/063754 or WO 2008/056746, indenocarbazolederivatives, for example in accordance with WO 2010/136109, WO2011/000455 or WO 2013/041176, azacarbazole derivatives, for example inaccordance with EP 1617710, EP 1617711, EP 1731584, JP 2005/347160,bipolar matrix materials, for example in accordance with WO 2007/137725,silanes, for example in accordance with WO 2005/111172, azaboroles orboronic esters, for example in accordance with WO 2006/117052, triazinederivatives, for example in accordance with WO 2010/015306, WO2007/063754 or WO 2008/056746, zinc complexes, for example in accordancewith EP 652273 or WO 2009/062578, diazasilole or tetraazasilolederivatives, for example in accordance with WO 2010/054729,diazaphosphole derivatives, for example in accordance with WO2010/054730, bridged carbazole derivatives, for example in accordancewith US 2009/0136779, WO 2010/050778, WO 2011/042107, WO 2011/088877 orWO 2012/143080, triphenylene derivatives, for example in accordance withWO 2012/048781, or lactams, for example in accordance with WO2011/116865 or WO 2011/137951.

More particularly, when the phosphorescent compound is employed in ahyperphosphorescent system as described above, the phosphorescentcompound is preferably selected from the phosphorescent organometalliccomplexes, which are described, for example, in WO2015/091716. Alsoparticularly preferred are the phosphorescent organometallic complexes,which are described in WO2000/70655, WO2001/41512, WO2002/02714,WO2002/15645, EP1191612, WO2005/033244, WO2005/019373, US2005/0258742,WO2006/056418, WO2007/115970, WO2007/115981, WO2008/000727,WO2009/050281, WO2009/050290, WO2011/051404, WO2011/073149,WO2012/121936, US2012/0305894, WO2012/170571, WO2012/170461,WO2012/170463, WO2006/121811, WO2007/095118, WO2008/156879,WO2008/156879, WO2010/068876, WO2011/106344, WO2012/172482, EP3126371,WO2015/014835, WO2015/014944, WO2016/020516, US20160072081,WO2010/086089, WO2011/044988, WO2014/008982, WO2014/023377,WO2014/094961, WO2010/069442, WO2012/163471, WO2013/020631,US20150243912, WO2008/000726, WO2010/015307, WO2010/054731,WO2010/054728, WO2010/099852, WO2011/032626, WO2011/157339,WO2012/007086, WO2015/036074, WO2015/104045, WO2015/117718,WO2016/015815, which are preferably iridium and platinum complexes.

Particularly preferred are also the phosphorescent organometalliccomplexes having polypodal ligands as described, for example, inWO2004/081017, WO2005/042550, US2005/0170206, WO2009/146770,WO2010/102709, WO2011/066898, WO2016124304, WO2017/032439,WO2018/019688, EP3184534 and WO2018/011186.

Particularly preferred are also the phosphorescent binuclearorganometallic complexes as described, for example, in WO2011/045337,US20150171350, WO2016/079169, WO2018/019687, WO2018/041769,WO2018/054798, WO2018/069196, WO2018/069197, WO2018/069273.

Particularly preferred are also the copper complexes as described, forexample, in WO2010/031485, US2013150581, WO2013/017675, WO2013/007707,WO2013/001086, WO2012/156378, WO2013/072508, EP2543672.

Explicit examples of phosphorescent sensitizers are Ir(ppy)₃ and itsderivatives as well as the structures listed below:

Further explicit examples of phosphorescent sensitizers are iridium andplatinum complexes containing carbene ligands and the structures listedbelow, wherein homoleptic and heteroleptic complexes and meridonal andfacial isomers may be suitable:

Further explicit examples of phosphorescent sensitizers are also coppercomplexes and the structures listed below:

Besides the compounds according to the invention, suitable TADFcompounds are compounds in which the energy gap between the lowesttriplet state T₁ and the first excited singlet state S₁ is sufficientlysmall that the S1 state is thermally accessible from the T1 state.Preferably, TADF compounds have a gap between the lowest triplet stateT₁ and the first excited singlet state S₁ of ≤0.30 eV. More preferably,the gap between S₁ and T₁ is ≤0.20 eV, even more preferably ≤0.15 eV,especially more preferably ≤0.10 eV and even more especially preferably≤0.08 eV.

The energy of the lowest excited singlet state (Si) and the lowesttriplet state (T₁) as well as the HOMO and LUMO values are determined byquantum-chemical calculations. The Gaussian09 program package (revisionD or later) is used. Neutral ground state geometries of all purelyorganic molecules are optimized at the AM1 level of theory.Subsequently, B3PW91/6-31G(d) single point calculations including acalculation of the lowest singlet and triplet excited states withTD-B3PW91/6-31G(d). HOMO and LUMO values as well as S1 and T1 excitationenergies are taken from this single-point calculation at theB3PW91/6-31G(d) level of theory.

Similarly, for metalorganic compounds, neutral ground state geometriesare optimized at the HF/LANL2 MB level of theory. B3PW91/6-31G(d)+LANL2DZ (LANL2DZ for all metal atoms, 6-31G(d) for all low-weightelements) is subsequently employed to calculate HOMO and LUMO values aswell as TD-DFT excitation energies.

HOMO (HEh) and LUMO (LEh) values from the calculation are given inHartree units. The HOMO and LUMO energy levels calibrated with referenceto cyclic voltammetry measurements are determined therefrom in electronvolts as follows:

HOMO(eV)=((HEh*27.212)−0.9899)/1.1206

LUMO(eV)=((LEh*27.212)−2.0041)/1.385

These values are to be regarded in the sense of the present invention asHOMO and LUMO energy levels of the materials.

The lowest triplet state T₁ is defined as the energy of the lowestTD-DFT triplet excitation energy.

The lowest excited singlet state S₁ is defined as the energy of thelowest TD-DFT singlet excitation energy.

Preferably, the TADF compound is an organic compound. Organic compoundsin the context of the present invention are carbonaceous compounds thatdo not contain any metals. More particularly, organic compounds areformed from the elements C, H, D, B, Si, N, P, O, S, F, Cl, Br and I.

The TADF compound is more preferably an aromatic compound having bothdonor and acceptor substituents, with only slight spatial overlapbetween the LUMO and the HOMO of the compound. What is understood bydonor and acceptor substituents is known in principle to those skilledin the art. Suitable donor substituents are especially diaryl- or-heteroarylamino groups and carbazole groups or carbazole derivatives,each preferably bonded to the aromatic compound via N. These groups mayalso have further substitution. Suitable acceptor substituents areespecially cyano groups, but also, for example, electron-deficientheteroaryl groups which may also have further substitution, for examplesubstituted or unsubstituted triazine groups.

The preferred dopant concentrations of the TADF compound in the emittinglayer are described hereinafter. Because of the difference in productionof the organic electroluminescent device, the dopant concentration inthe case of production of the emitting layer by vapor deposition isreported in % by volume, and in the case of production of the emittinglayer from solution in % by weight. The dopant concentrations in % byvolume and % by weight is generally very similar.

In a preferred embodiment of the invention, in the case of production ofthe emitting layer by vapor deposition, the TADF compound is present ina dopant concentration of 1% to 70% by volume in the emitting layer,more preferably of 5% to 50% by volume, even more preferably of 5% to30% by volume.

In a preferred embodiment of the invention, in the case of production ofthe emitting layer from solution, the TADF compound is present in adopant concentration of 1% to 70% by weight in the emitting layer, morepreferably of 5% to 50% by weight, even more preferably of 5% to 30% byweight.

The general art knowledge of the person skilled in the art includesknowledge of which materials are generally suitable as TADF compounds.The following references disclose, by way of example, materials that arepotentially suitable as TADF compounds:

-   -   Tanaka et al., Chemistry of Materials 25(18), 3766 (2013).    -   Lee et al., Journal of Materials Chemistry C 1(30), 4599 (2013).    -   Zhang et al., Nature Photonics advance online publication, 1        (2014), doi: 10.1038/nphoton.2014.12.    -   Serevicius et al., Physical Chemistry Chemical Physics 15(38),        15850 (2013).    -   Li et al., Advanced Materials 25(24), 3319 (2013).    -   Youn Lee et al., Applied Physics Letters 101(9), 093306 (2012).    -   Nishimoto et al., Materials Horizons 1, 264 (2014), doi:        10.1039/C3MH00079F.    -   Valchanov et al., Organic Electronics, 14(11), 2727 (2013).    -   Nasu et al., ChemComm, 49, 10385 (2013).

In addition, the following patent applications disclose potential TADFcompounds: US2019058130, WO18155642, WO18117179A1, US2017047522,US2016372682A, US2015041784, US2014336379, US2014138669, WO 2013/154064,WO 2013/133359, WO 2013/161437, WO 2013/081088, WO 2013/081088, WO2013/011954, JP 2013/116975 und US 2012/0241732.

In addition, the person skilled in the art is able to infer designprinciples for TADF compounds from these publications. For example,Valchanov et al. show how the colour of TADF compounds can be adjusted.

Examples of suitable molecules which exhibit TADF are the structuresshown in the following table:

As mentioned above, the compounds of formula (1) or in accordance withthe preferred embodiments may be used as fluorescent emitters incombinations with a sensitizer in a hyperfluorescent orhyperphosphorescent system. In this case, it is preferred that thecompounds of formula (1) are sterically shielded. For examples compoundsof formula (1) corresponding to compounds of formulae (5) and (6), moreparticularly (5-1) to (5-3), are very suitable as sterically shieldedfluorescent emitters in combination with a sensitizer selected from TADFcompounds and phosphorescent compounds in an emitting layer. Preferably,the emitting layer further comprises at least one organic functionalmaterial selected from matrix materials.

The compounds of formula (1) or in accordance with preferred embodimentscan also be employed in combination with further compounds selected fromthe group consisting of HTM (Hole Transport Material), HIM (HoleInjection Material), HBM (Hole Blocking Material), p-dopant, ETM(Electron Transport Material), EIM (Electron Injection Material), EBM(Electron Blocking Material), n-dopant, fluorescent emitter,phosphorescent emitter, delayed fluorescent emitter, matrix material,host material, wide band gap material and quantum material, like quantumdot and quantum rod.

The compounds of formula (1) or in accordance with preferred embodimentscan also be employed in other layers, for example as hole-transportmaterials in a hole-injection or hole-transport layer orelectron-blocking layer or as matrix materials in an emitting layer.

Generally preferred classes of material for use as correspondingfunctional materials in the organic electroluminescent devices accordingto the invention are indicated below.

Suitable charge-transport materials, as can be used in thehole-injection or hole-transport layer or electron-blocking layer or inthe electron-transport layer of the electronic device according to theinvention, are, for example, the compounds disclosed in Y. Shirota etal., Chem. Rev. 2007, 107(4), 953-1010, or other materials as areemployed in these layers in accordance with the prior art.

Materials which can be used for the electron-transport layer are allmaterials as are used in accordance with the prior art aselectron-transport materials in the electron-transport layer.Particularly suitable are aluminium complexes, for example Alq₃,zirconium complexes, for example Zrq₄, lithium complexes, for exampleLiQ, benzimidazole derivatives, triazine derivatives, pyrimidinederivatives, pyridine derivatives, pyrazine derivatives, quinoxalinederivatives, quinoline derivatives, oxadiazole derivatives, aromaticketones, lactams, boranes, diazaphosphole derivatives and phosphineoxide derivatives. Furthermore, suitable materials are derivatives ofthe above-mentioned compounds, as disclosed in JP 2000/053957, WO2003/060956, WO 2004/028217, WO 2004/080975 and WO 2010/072300.

Preferred hole-transport materials which can be used in ahole-transport, hole-injection or electron-blocking layer in theelectroluminescent device according to the invention areindenofluorenamine derivatives (for example in accordance with WO06/122630 or WO 06/100896), the amine derivatives disclosed in EP1661888, hexaazatriphenylene derivatives (for example in accordance withWO 01/049806), amine derivatives containing condensed aromatic rings(for example in accordance with U.S. Pat. No. 5,061,569), the aminederivatives disclosed in WO 95/09147, monobenzoindenofluorenamines (forexample in accordance with WO 08/006449), dibenzoindenofluorenamines(for example in accordance with WO 07/140847), spirobifluorenamines (forexample in accordance with WO 2012/034627 or WO 2013/120577),fluorenamines (for example in accordance with the as applications EP2875092, EP 2875699 and EP 2875004), spirodibenzopyranamines (forexample in accordance with WO 2013/083216) and dihydroacridinederivatives (for example in accordance with WO 2012/150001). Thecompounds according to the invention can also be used as hole-transportmaterials.

The cathode of the organic electroluminescent device preferablycomprises metals having a low work function, metal alloys ormultilayered structures comprising various metals, such as, for example,alkaline-earth metals, alkali metals, main-group metals or lanthanoids(for example Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.). Also suitable arealloys comprising an alkali metal or alkaline-earth metal and silver,for example an alloy comprising magnesium and silver. In the case ofmultilayered structures, further metals which have a relatively highwork function, such as, for example, Ag or Al, can also be used inaddition to the said metals, in which case combinations of the metals,such as, for example, Ca/Ag, Mg/Ag or Ag/Ag, are generally used. It mayalso be preferred to introduce a thin interlayer of a material having ahigh dielectric constant between a metallic cathode and the organicsemiconductor. Suitable for this purpose are, for example, alkali metalfluorides or alkaline-earth metal fluorides, but also the correspondingoxides or carbonates (for example LiF, Li₂O, BaF₂, MgO, NaF, CsF,Cs₂CO₃, etc.). Furthermore, lithium quinolinate (LiQ) can be used forthis purpose. The layer thickness of this layer is preferably between0.5 and 5 nm.

The anode preferably comprises materials having a high work function.The anode preferably has a work function of greater than 4.5 eV vs.vacuum. Suitable for this purpose are on the one hand metals having ahigh redox potential, such as, for example, Ag, Pt or Au. On the otherhand, metal/metal oxide electrodes (for example Al/Ni/NiO_(x),Al/PtO_(x)) may also be preferred. For some applications, at least oneof the electrodes must be transparent or partially transparent in orderto facilitate either irradiation of the organic material (organic solarcells) or the coupling-out of light (OLEDs, O-lasers). Preferred anodematerials here are conductive mixed metal oxides. Particular preferenceis given to indium tin oxide (ITO) or indium zinc oxide (IZO).Preference is furthermore given to conductive, doped organic materials,in particular conductive doped polymers.

The device is appropriately (depending on the application) structured,provided with contacts and finally sealed, since the lifetime of thedevices according to the invention is shortened in the presence of waterand/or air.

In a preferred embodiment, the organic electroluminescent deviceaccording to the invention is characterised in that one or more layersare coated by means of a sublimation process, in which the materials areapplied by vapour deposition in vacuum sublimation units at an initialpressure of less than 10⁻⁵ mbar, preferably less than 10⁻⁶ mbar.However, it is also possible here for the initial pressure to be evenlower, for example less than 10⁻⁷ mbar.

Preference is likewise given to an organic electroluminescent device,characterised in that one or more layers are coated by means of the OVPD(organic vapour phase deposition) process or with the aid of carrier-gassublimation, in which the materials are applied at a pressure of between10⁻⁵ mbar and 1 bar. A special case of this process is the OVJP (organicvapour jet printing) process, in which the materials are applieddirectly through a nozzle and are thus structured (for example M. S.Arnold et al., Appl. Phys. Lett. 2008, 92, 053301).

Preference is furthermore given to an organic electroluminescent device,characterised in that one or more layers are produced from solution,such as, for example, by spin coating, or by means of any desiredprinting process, such as, for example, screen printing, flexographicprinting, nozzle printing or offset printing, but particularlypreferably LITI (light induced thermal imaging, thermal transferprinting) or ink-jet printing. Soluble compounds of the formula (I) arenecessary for this purpose. High solubility can be achieved throughsuitable substitution of the compounds.

Also possible are hybrid processes, in which, for example, one or morelayers are applied from solution and one or more further layers areapplied by vapour deposition. Thus, it is possible, for example, toapply the emitting layer from solution and to apply theelectron-transport layer by vapour deposition.

These processes are generally known to the person skilled in the art andcan be applied by him without inventive step to organicelectroluminescent devices comprising the compounds according to theinvention.

In accordance with the invention, the electronic devices comprising oneor more compounds according to the invention can be employed indisplays, as light sources in lighting applications and as light sourcesin medical and/or cosmetic applications (for example light therapy).

The invention will now be explained in greater detail by the followingexamples, without wishing to restrict it thereby.

A) SYNTHESES EXAMPLES Example 1: Compound 1

Amine [1] [850264-79-8]

Synthesized according to literature. Journal of Polymer Science Part APolymer Chemistry Volume: 57 Issue 1 (2019) 70-76.

Bromide [2]

A flask under Ar atmosphere is charged with amine [1] [850264-79-8] (5.0g, 10.6 mmol, 1.0 equiv.), 1,3-dibromo-2-fluorobenzene [1435-54-7] (2.8g, 10.6 mmol, 1.0 equiv.), potassium phosphate (4.5 g, 21.2 mmol, 2.0equiv.) and N,N-dimethyl acetamide (250 mL). The mixture is refluxed for2 h. The mixture is cooled to room temperature (rt). Water (250 mL) isadded. The forming precipitate is collected. The desired product isisolated as white solid (7.0 g, 9.9 mmol, 94%).

Compound 1 [3]

A flask under Ar atmosphere is charged with bromide [2] (500 mg, 0.7mmol, 1.0 equiv.) and tert-butylbenzene (20 mL). The mixture is cooleddown to −41° C. Then tert-butyllithium (1.7 M in pentane, 1.9 mL, 3.2mmol, 4.5 equiv.) is added. The reaction mixture is allowed to warm tort. Then the reaction mixture is heated to 100° C. for 1 h. The reactionmixture is cooled back to −41° C. and BBr₃ (0.2 mL, 1.8 mmol, 2.5equiv.) is added. The reaction mixture is allowed to warm to 0° C. Thereaction mixture is stirred for 1 h at this temperature, beforeN,N-diisopropylethylamine (0.3 mL, 1.4 mmol, 2.4 equiv.) is added. Thereaction mixture is refluxed for 16 h. Then the reaction mixture iscooled down to −78° C. and 2-Mesitylmagnesium bromide (700 mg, 3.0 mmol,4.3 equiv.) is added. The resulting mixture is allowed to warm to rt.The solvent is removed, and the crude product is purified by columnchromatography. The desired product is isolated as yellow solid (50 mg,0.07 mmol, 10%).

Example 2: Compound 2 2-Bromo-1-fluoro-4-phenylbenzene [9]

A Schlenk flask was charged with 2-bromo-1-fluoro-4-iodobenzene (3.0 g,10 mmol), phenyl boronic acid (1.3 g, 11 mmol), and sodium carbonate(2.1 g, 20 mmol) under argon. Toluene (9 ml), water (6 ml), ethanol (3ml), Pd(OAc)₂ (23 mg, 0.1 mmol), and PPh₃ (79 mg, 0.3 mmol) were added.It was heated to 50° C. for 1.5 h, to 60° C. for 18 h, and to 80° C. for23 h. It was subjected to extractive work-up with water/dichloromethane.The residue was passed through silica with n-hexane. Yield: 2.44 g(97%).

9-(2-Bromo-4-phenylphenyl)-3,6-bis(4-phenylphenyl)carbazole [10]

A Schlenk flask was charged with [1] (3.6 g, 7.5 mmol), [9] (1.9 g, 7.6mmol), and K₃PO₄ (3.2 g, 15 mmol) under argon. Dimethylacetamide (75 ml)was added, and it was heated to reflux for 18 h. More [9] (˜200 mg) wasadded and refluxing was continued for 2 h. It was diluted with water andthe precipitated solid filtered off and washed with water. It was driedunder air and washed with methanol and dichloromethane. The filtrate wasevaporated and the residue was subjected to column chromatography (SiO₂,dichloromethane/n-hexane 1:2). Yield: 2.3 g (43%).

3,6-bis(4-phenylphenyl)-9-[4-phenyl-2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]carbazole[11]

[10] (774 mg, 1.1 mmol), B₂pin₂ (559 mg, 2.2 mmol), and CsF (501 mg, 3.3mmol) were dissolved in dry THF (8 ml) under argon. PdCl₂(PCy₃)₂ (41 mg,0.06 mmol) was added and it was heated to reflux for 2 h. The solventwas evaporated, the residue stirred with dichloromethane, and it wasfiltered. The filtrate was evaporated, and the residue was subjected tocolumn chromatography (SiO₂, n-hexane/ethyl acetate 10:1). Yield: 829 mg(100%)

2-bromo-1,3,5-triphenylbenzene [12]

Bromine (3.2 g, 20 mmol) was slowly added to a stirred suspension of1,3,5-triphenylbenzene (5.1 g, 17 mmol) in dichloromethane (30 ml) andacetic acid (6 ml). It was stirred at 40° C. for 16 h. Water (30 ml) wasadded and excess bromine was quenched with solid Na₂SO₃. It wasalkalised with 25% NHaaq and layers were separated. The organic layerwas washed with 0.1 M NHaaq, dried with MgSO₄ and evaporated. Theresidue was recrystallized from tBuOMe and ethanol. The precipitatedsolid was filtered off and washed with ethanol. Yield: 5.97 g (93%).

Compound 2 [13]

A Schlenk tube was charged with [11] (420 mg, 0.56 mmol) and AlCl₃ (373mg, 2.8 mmol) under argon. Dry toluene (3 ml) and DIPEA were added andit was heated to 100° C. for 2 h. The solvent was removed in vacuo andTHF (3 ml) was added. A solution of lithiated [12] (10 mmol in diethylether) was added dropwise at −72° C.

The cooling was removed, and it was stirred at room temperatureovernight. The solvent was removed in vacuo and it was filtered throughsilica with dichloromethane. The residue was subjected to columnchromatography (SiO₂, dichloromethane/n-hexane, gradient). Yield: 35 mg(6.7%)

Compound 3 [14]

[14] was synthesized in analogy to [13] using lithiated2-bromo-1,3,5-trimethylbenzene and [11] as starting materials.

Further structures can be synthesized using the following syntheticroute:

Compounds [4] are either commercially available or can be synthesized inSuzuki cross-coupling reactions using Pd(PPh₃)₄ in analogy toCN107721979A.

Ar₁—B(OH)₂ Compound [4]

CAS: 694-80-4

CAS: 98-80-6

CAS: 5122-94-1

CAS: 5720-05-8

CAS: 5980-97-2

Compounds [6] are either commercially available or can be synthesized inSuzuki cross-coupling reactions in analogy to Amine [1].

Compound [5] Ar₂—B(OH)₂ Compound [6]

CAS: 86-74-8

CAS: 6825-20-3 CAS: 98-80-6

CAS: 6825-20-3 CAS: 5122-94-1 Amine [1]

CAS: 6825-20-3 CAS: 5980-97-2

CAS: 6825-20-3 CAS: 4688-76-0

CAS: 194-59-2

CAS: 135-67-1

CAS: 832734-16-4 CAS: 5122-94-1

CAS: 578-95-0

CAS: 1209-66-1

CAS: 29875-73-8

CAS: 6267-02-3

CAS: 92638-81-8

Compounds [7] can be synthesized in Ullmann cross-coupling reactions inanalogy to WO2016195441A1.

Compound [4] Compound [6] Compound [7]

CAS: 194-59-2

CAS: 135-67-1

CAS: 578-95-0

CAS: 1209-66-1

CAS: 29875-73-8

CAS: 6267-02-3

CAS: 92638-81-8

Compounds [8] can be synthesized in analogy to compound 1 [3].

Compound [7] Ar₃—M Compound [8]

M = MgBr, CAS: 2633-66-1

M = MgBr, CAS: 36719-77-4

M = MgBr, CAS: 2633-66-1

M = MgBr, CAS: 2633-66-1

M = MgBr, CAS: 36719-77-4

M = MgBr, CAS: 2633-66-1

M = MgBr, CAS: 2633-66-1

M = MgBr, CAS: 36719-77-4

M = MgBr, CAS: 36719-77-4

M = MgBr, CAS: 2633-66-1

M = MgBr, CAS: 36719-77-4

M = MgBr, CAS: 36719-77-4

M = MgBr, CAS: 36719-77-4

M = MgBr, CAS: 36719-77-4

B) Fabrication of OLEDs

The compounds of the present invention can be used as triplet matrixmaterial in the light emitting layer of an OLED or as fluorescentemitter in the light emitting layer of an OLED.

Determination of peak emission wavelength X_(max)

To determine the peak emission wavelength of the fluorescent emitter,the fluorescent emitter is dissolved in toluene. A concentration of 1mg/100 mL is used. The solution is excited in a fluorescencespectrometer Hitachi F4500 with a to the material matching wavelength.The measurement is carried out at room temperature. The peak emissionwavelength λ_(max) is the wavelength of the first maximum of theemission spectrum (FIG. 1 ). Typically, the first maximum is also theglobal maximum of the spectrum.

The peak emission wavelength λ_(max) of the compounds [8] depicted aboveis in the range of 400 nm to 500 nm.

Determination of the spectral broadness (full width at half maximum(FWHM))

To determine the spectral broadness of the fluorescent emitter, thevalues for the wavelengths (X1, X2) (see FIG. 1 ) which are at half themaximum of the peak emission wavelength (y=0.5) are subtracted. The fullwidth at half maximum is calculated according to formula (1):

FWHM=X2−X1  (1)

According to the described methods the following properties for thefluorescent emitters are obtained and depicted in the following table:

Material λ_(max) FWHM [nm] CIE-y Ex-1-3-2 478 37 0.19  Compound 1 442 310.045 Compound 2 456 30 0.070 Compound 3 451 33 0.061

Properties of Ex-1-3-2 as depicted below are shown in WO18047639A1 fromJNC. Inventive Compounds 1-3 show a narrower spectrum and have thus ahigher colour purity.

Chemical structure of Ex-1-3-2 from WO18047639A1:

1.-25. (canceled)
 26. A compound of the formula (1),

where X¹ stands, on each occurrence, identically or differently, for CR¹or N; X² stands, on each occurrence, identically or differently, for CR²or N; X^(A) stands, on each occurrence, identically or differently, forCR^(A) or N; Y is a single bond or a divalent bridge selected from—C(R^(Y))₂—, —C(R^(Y))₂—C(R^(Y))₂—, —O—, —S—, —S(═O)₂— and —C(═O)—;R^(B) stands on each occurrence, identically or differently, for CN,N(Ar)₂, C(═O)Ar, P(═O)(Ar)₂, S(═O)Ar, S(═O)₂Ar, N(R)₂, Si(R)_(3,2),OSO₂R, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40carbon atoms or an alkenyl or alkynyl group having 2 to 40 carbon atomsor a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 40carbon atoms, each of which may be substituted by one or more radicalsR, where in each case one or more non-adjacent CH₂ groups may bereplaced by RC═CR, C≡C, Si(R)₂, Ge(R)₂, Sn(R)₂, C═O, C═S, C═Se,P(═O)(R), SO, So₂, O, S or CONR and where one or more H atoms may bereplaced by D, F, Cl, Br, I, CN or NO₂, or an aromatic or heteroaromaticring system having 5 to 60 aromatic ring atoms, which may in each casebe substituted by one or more radicals R, or an aryloxy group having 5to 60 aromatic ring atoms, which may be substituted by one or moreradicals R, or an aralkyl or heteroaralkyl group which has 5 to 60aromatic ring atoms, which may be substituted by one or more R radicals;R^(Y) stands on each occurrence, identically or differently, for H, D,F, Cl, Br, I, CHO, CN, N(Ar)₂, C(═O)Ar, P(═O)(Ar)₂, S(═O)Ar, S(═O)₂Ar,NO₂, N(R)₂, Si(R)₃, B(OR)₂, OSO₂R, a straight-chain alkyl, alkoxy orthioalkoxy group having 1 to 40 carbon atoms or an alkenyl or alkynylgroup having 2 to 40 carbon atoms or a branched or cyclic alkyl, alkoxyor thioalkoxy group having 3 to 40 carbon atoms, each of which may besubstituted by one or more radicals R, where in each case one or morenon-adjacent CH₂ groups may be replaced by RC═CR, C≡C, Si(R)₂, Ge(R)₂,Sn(R)₂, C═O, C═S, C═Se, P(═O)(R), SO, SO₂, O, S or CONR and where one ormore H atoms may be replaced by D, F, Cl, Br, I, CN or NO₂, or anaromatic or heteroaromatic ring system having 5 to 60 aromatic ringatoms, which may in each case be substituted by one or more radicals R,or an aryloxy group having 5 to 60 aromatic ring atoms, which may besubstituted by one or more radicals R, or an aralkyl or heteroaralkylgroup which has 5 to 60 aromatic ring atoms, which may be substituted byone or more R radicals; where two adjacent substituents R^(Y) may form amono- or polycyclic, aliphatic ring system or aromatic ring system,which may be substituted by one or more radicals R′; R¹, R², R^(A) standon each occurrence, identically or differently, for H, D, F, Cl, Br, I,CHO, CN, N(Ar)₂, C(═O)Ar, P(═O)(Ar)₂, S(═O)Ar, S(═O)₂Ar, NO₂, Si(R)₃,B(OR)₂, OSO₂R, a straight-chain alkyl, alkoxy or thioalkyl group having1 to 40 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl groupshaving 3 to 40 C atoms, each of which may be substituted by one or moreradicals R, where in each case one or more non-adjacent CH₂ groups maybe replaced by RC═CR, C≡C, Si(R)₂, Ge(R)₂, Sn(R)₂, C═O, C═S, C═Se,P(═O)(R), SO, SO₂, O, S or CONR and where one or more H atoms may bereplaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromaticring system having 5 to 60 aromatic ring atoms, which may in each casebe substituted by one or more radicals R, an aryloxy group having 5 to60 aromatic ring atoms, which may be substituted by one or more radicalsR, or an aralkyl or heteroaralkyl group which has 5 to 60 aromatic ringatoms, which may be substituted by one or more R radicals; where twoadjacent radicals selected from R¹, R², R^(A) may form a mono- orpolycyclic, aliphatic ring system or aromatic ring system, which may besubstituted by one or more radicals R; R stands on each occurrence,identically or differently, for H, D, F, Cl, Br, I, CHO, CN, N(Ar)₂,C(═O)Ar, P(═O)(Ar)₂, S(═O)Ar, S(═O)₂Ar, NO₂, Si(R′)₃, B(OR′)₂, OSO₂R, astraight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atomsor branched or cyclic alkyl, alkoxy or thioalkyl groups having 3 to 40 Catoms, each of which may be substituted by one or more radicals R′,where in each case one or more non-adjacent CH₂ groups may be replacedby R′C═CR′, C≡C, Si(R′)₂, Ge(R′)₂, Sn(R′)₂, C═O, C═S, C═Se, P(═O)(R′),SO, SO₂, O, S or CONR′ and where one or more H atoms may be replaced byD, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring systemhaving 5 to 60 aromatic ring atoms, which may in each case besubstituted by one or more radicals R′, or an aryloxy group having 5 to60 aromatic ring atoms, which may be substituted by one or more radicalsR′, where two adjacent radicals R may form a mono- or polycyclic,aliphatic ring system or aromatic ring system, which may be substitutedby one or more radicals R′; Ar is on each occurrence, identically ordifferently, an aromatic or heteroaromatic ring system having 5 to 24aromatic ring atoms, which may in each case also be substituted by oneor more radicals R′; R′ stands on each occurrence, identically ordifferently, for H, D, F, Cl, Br, I, CN, a straight-chain alkyl, alkoxyor thioalkyl group having 1 to 20 C atoms or branched or cyclic alkyl,alkoxy or thioalkyl group having 3 to 20 C atoms, where in each case oneor more non-adjacent CH₂ groups may be replaced by SO, SO₂, O, S andwhere one or more H atoms may be replaced by D, F, Cl, Br or I, or anaromatic or heteroaromatic ring system having 5 to 24 C atoms.
 27. Thecompound according to claim 26, wherein the compound is selected fromcompounds of formula (2),

where the symbols have the same meaning as in claim
 26. 28. The compoundaccording to claim 26, wherein the compound is selected from compoundsof formula (3),

where the symbols have the same meaning as in claim
 26. 29. The compoundaccording to claim 26, wherein R^(B) stands on each occurrence,identically or differently, for a straight-chain alkyl, alkoxy orthioalkoxy group having 1 to 40 carbon atoms or an alkenyl or alkynylgroup having 2 to 40 carbon atoms or a branched or cyclic alkyl, alkoxyor thioalkoxy group having 3 to 40 carbon atoms, each of which may besubstituted by one or more radicals R, where in each case one or morenon-adjacent CH₂ groups may be replaced by RC═CR, C≡C, Si(R)₂, Ge(R)₂,Sn(R)₂, C═O, C═S, C═Se, P(═O)(R), SO, SO₂, O, S or CONR and where one ormore H atoms may be replaced by D, F, Cl, Br, I, CN or NO₂, or anaromatic or heteroaromatic ring system having 5 to 60 aromatic ringatoms, which may in each case be substituted by one or more radicals R,or an aralkyl or heteroaralkyl group which has 5 to 60 aromatic ringatoms, which may be substituted by one or more R radicals.
 30. Thecompound according to claim 26, wherein R^(B) stands on each occurrence,identically or differently, for a straight-chain alkyl or alkoxy grouphaving 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to20 carbon atoms or a branched or cyclic alkyl or alkoxy group having 3to 20 carbon atoms, each of which may be substituted by one or moreradicals R, where one or more H atoms may be replaced by D, F, Cl or CN,or an aromatic ring system having 5 to 60 aromatic ring atoms, which mayin each case be substituted by one or more radicals R, or an aralkyl orheteroaralkyl group which has 5 to 60 aromatic ring atoms, which may besubstituted by one or more R radicals.
 31. The compound according toclaim 26, wherein R^(B) is selected on each occurrence, identically ordifferently, from branched or cyclic alkyl groups represented by thegeneral following formula (RS-a)

wherein R²², R²³, R²⁴ are at each occurrence, identically ordifferently, selected from H, a straight-chain alkyl group having 1 to10 carbon atoms, or a branched or cyclic alkyl group having 3 to 10carbon atoms, where the above-mentioned groups may each be substitutedby one or more radicals R²⁵, and where two of radicals R²², R²³, R²⁴ orall radicals R²², R²³, R²⁴ may be joined to form a (poly)cyclic alkylgroup, which may be substituted by one or more radicals R²⁵; R²⁵ is ateach occurrence, identically or differently, selected from astraight-chain alkyl group having 1 to 10 carbon atoms, or a branched orcyclic alkyl group having 3 to 10 carbon atoms; with the proviso that ateach occurrence at least one of radicals R²², R²³ and R²⁴ is other thanH, with the proviso that at each occurrence all of radicals R²², R²³ andR²⁴ together have at least 4 carbon atoms and with the proviso that ateach occurrence, if two of radicals R²², R²³, R²⁴ are H, the remainingradical is not a straight-chain; or from branched or cyclic alkoxygroups represented by the general following formula (RS-b)

wherein R²⁶, R²⁷, R²⁸ are at each occurrence, identically ordifferently, selected from H, a straight-chain alkyl group having 1 to10 carbon atoms, or a branched or cyclic alkyl group having 3 to 10carbon atoms, where the above-mentioned groups may each be substitutedby one or more radicals R²⁵ as defined above, and where two of radicalsR²⁶, R²⁷, R²⁸ or all radicals R²⁶, R²⁷, R²⁸ may be joined to form a(poly)cyclic alkyl group, which may be substituted by one or moreradicals R²⁵ as defined above; with the proviso that at each occurrenceonly one of radicals R²⁶, R²⁷ and R²⁸ may be H; or from aralkyl groupsrepresented by the general following formula (RS-c)

wherein R²⁹, R³⁰, R³¹ are at each occurrence, identically ordifferently, selected from H, a straight-chain alkyl group having 1 to10 carbon atoms, or a branched or cyclic alkyl group having 3 to 10carbon atoms, where the above-mentioned groups may each be substitutedby one or more radicals R³², or an aromatic ring system having 6 to 30aromatic ring atoms, which may in each case be substituted by one ormore radicals R³², and where two or all of radicals R²⁹, R³⁰, R³¹ may bejoined to form a (poly)cyclic alkyl group or an aromatic ring system,each of which may be substituted by one or more radicals R³²; R³² is ateach occurrence, identically or differently, selected from astraight-chain alkyl group having 1 to 10 carbon atoms, or a branched orcyclic alkyl group having 3 to 10 carbon atoms, or an aromatic ringsystem having 6 to 24 aromatic ring atoms; with the proviso that at eachoccurrence at least one of radicals R²⁹, R³⁰ and R³¹ is other than H andthat at each occurrence at least one of radicals R²⁹, R³⁰ and R³¹ is orcontains an aromatic ring system having at least 6 aromatic ring atoms;or from aromatic ring systems represented by the general followingformula (RS-d)

wherein R⁴⁰ to R⁴⁴ is at each occurrence, identically or differently,selected from H, a straight-chain alkyl group having 1 to 10 carbonatoms, or a branched or cyclic alkyl group having 3 to 10 carbon atoms,where the above-mentioned groups may each be substituted by one or moreradicals R³², or an aromatic ring system having 6 to 30 aromatic ringatoms, which may in each case be substituted by one or more radicalsR³², and where two or more of radicals R⁴⁰ to R⁴⁴ may be joined to forma (poly)cyclic alkyl group or an aromatic ring system, each of which maybe substituted by one or more radicals R³² as defined above.
 32. Thecompound according to claim 26, wherein R² and R^(A) stand on eachoccurrence, identically or differently, for H, D, F, Cl, Br, I, CN,N(Ar)₂, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40C atoms or branched or cyclic alkyl, alkoxy or thioalkyl groups having 3to 40 C atoms, each of which may be substituted by one or more radicalsR, where in each case one or more non-adjacent CH₂ groups may bereplaced by RC═CR, C≡C, Si(R)₂, Ge(R)₂, Sn(R)₂, C═O, C═S, C═Se,P(═O)(R), SO, SO₂, O, S or CONR and where one or more H atoms may bereplaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromaticring system having 5 to 60 aromatic ring atoms, which may in each casebe substituted by one or more radicals R, or an aralkyl or heteroaralkylgroup which has 5 to 60 aromatic ring atoms, which may be substituted byone or more R radicals.
 33. The compound according to claim 26 whereinR² and R^(A) stand on each occurrence, identically or differently, forH, D, F, CN, a straight-chain alkyl, alkoxy or thioalkyl group having 1to 40 C atoms or branched or cyclic alkyl, alkoxy or thioalkyl groupshaving 3 to 40 C atoms, each of which may be substituted by one or moreradicals R, where in each case one or more non-adjacent CH₂ groups maybe replaced by RC═CR, C≡C, O or S and where one or more H atoms may bereplaced by D, F, an aromatic or heteroaromatic ring system having 5 to60 aromatic ring atoms, which may in each case be substituted by one ormore radicals R or an aralkyl or heteroaralkyl group which has 5 to 60aromatic ring atoms, which may be substituted by one or more R radicals.34. The compound according to claim 26, wherein R² and R^(A) stand oneach occurrence, identically or differently, for H, D, F, CN; or for agroup of formula (RS-a), a group of formula (RS-b), a group of formula(RS-c) or a group of formula (RS-d), where the groups of formulae(RS-a), (RS-b), (RS-c) and (RS-d) have the same definition as in claim31; or for a group of formula (ArL-1),

where the dashed bond in formula (ArL-1) indicates the bonding to thestructure of formula (1), where Ar², Ar³ stand on each occurrence,identically or differently, for an aromatic or heteroaromatic ringsystems having 5 to 60 aromatic ring atoms, which may in each case besubstituted by one or more radicals R; and where m is an integerselected from 1 to
 10. 35. The compound according to claim 26, whereinthe compound is selected from compounds of formula (4),

where the symbols have the same meaning as in claim
 26. 36. The compoundaccording to claim 31, wherein R^(B) and R^(A) are on each occurrence,identically or differently, selected from the groups of formulae (RS-a),(RS-b), (RS-c) and (RS-d), where the groups of formulae (RS-a), (RS-b),(RS-c) and (RS-d) have the same definition as in claim
 31. 37. Thecompound according to claim 26, wherein the compound is selected fromcompounds of formula (5) or (6),

wherein the group R^(A) has the same meaning as in claim 26, andwherein, in formula (5), R⁴⁰, R⁴², R⁴⁴ are at each occurrence,identically or differently, selected from H, a straight-chain alkylgroup having 1 to 10 carbon atoms, or a branched or cyclic alkyl grouphaving 3 to 10 carbon atoms, where the above-mentioned groups may eachbe substituted by one or more radicals R³², or an aromatic ring systemhaving 6 to 30 aromatic ring atoms, which may in each case besubstituted by one or more radicals R³²; R³² is at each occurrence,identically or differently, selected from a straight-chain alkyl grouphaving 1 to 10 carbon atoms, or a branched or cyclic alkyl group having3 to 10 carbon atoms, or an aromatic ring system having 6 to 24 aromaticring atoms; with the proviso that at each occurrence at least one ofradicals R²⁹, R³⁰ and R³¹ is other than H and that at each occurrence atleast one of radicals R²⁹, R³⁰ and R³¹ is or contains an aromatic ringsystem having at least 6 aromatic ring atoms; or from aromatic ringsystems represented by the general following formula (RS-d)

wherein R⁴⁰ to R⁴⁴ is at each occurrence, identically or differently,selected from H, a straight-chain alkyl group having 1 to 10 carbonatoms, or a branched or cyclic alkyl group having 3 to 10 carbon atoms,where the above-mentioned groups may each be substituted by one or moreradicals R³², or an aromatic ring system having 6 to 30 aromatic ringatoms, which may in each case be substituted by one or more radicalsR³², and where two or more of radicals R⁴⁰ to R⁴⁴ may be joined to forma (poly)cyclic alkyl group or an aromatic ring system, each of which maybe substituted by one or more radicals R³² as defined above; with theproviso that at least one of R⁴⁰, R⁴², R⁴⁴ is other than H; or

wherein, in formula (6), R⁴¹, R⁴³ are at each occurrence, identically ordifferently, selected from H, a straight-chain alkyl group having 1 to10 carbon atoms, or a branched or cyclic alkyl group having 3 to 10carbon atoms, where the above-mentioned groups may each be substitutedby one or more radicals R³², or an aromatic ring system having 6 to 30aromatic ring atoms, which may in each case be substituted by one ormore radicals R³²; with the proviso that at least one of R⁴¹, R⁴³ isother than H.
 38. Compound according to claim 37, wherein R⁴² is at eachoccurrence, identically or differently, selected from H, astraight-chain alkyl group having 1 to 10 carbon atoms, or a branched orcyclic alkyl group having 3 to 10 carbon atoms, where theabove-mentioned groups may each be substituted by one or more radicalsR³², or an aromatic ring system having 6 to 30 aromatic ring atoms,which may in each case be substituted by one or more radicals R³²; R⁴⁰,R⁴⁴ are at each occurrence, identically or differently, selected from anaromatic ring system having 6 to 30 aromatic ring atoms, which may ineach case be substituted by one or more radicals R³²; R³² is at eachoccurrence, identically or differently, selected from a straight-chainalkyl group having 1 to 10 carbon atoms, or a branched or cyclic alkylgroup having 3 to 10 carbon atoms, or an aromatic ring system having 6to 24 aromatic ring atoms; with the proviso that at each occurrence atleast one of radicals R²⁹, R³⁰ and R³¹ is other than H and that at eachoccurrence at least one of radicals R²⁹, R³⁰ and R³¹ is or contains anaromatic ring system having at least 6 aromatic ring atoms; or fromaromatic ring systems represented by the general following formula(RS-d)


39. The compound according to claim 26, wherein the compound is selectedfrom the compounds of formulae (5-1), (5-2) and (5-3),

where the group R^(A) has the same meaning as in claim 26, and where ineach of formulae (5-1), (5-2) and (5-3) the phenyl groups indicated with—R³² are unsubstituted or substituted with one or more radicals R³²; R⁴²and R⁴⁴ are at each occurrence, identically or differently, selectedfrom H, a straight-chain alkyl group having 1 to 10 carbon atoms, or abranched or cyclic alkyl group having 3 to 10 carbon atoms, where theabove-mentioned groups may each be substituted by one or more radicalsR³²; R³² is at each occurrence, identically or differently, selectedfrom a straight-chain alkyl group having 1 to 10 carbon atoms, or abranched or cyclic alkyl group having 3 to 10 carbon atoms, or anaromatic ring system having 6 to 24 aromatic ring atoms; with theproviso that at each occurrence at least one of radicals R²⁹, R³⁰ andR³¹ is other than H and that at each occurrence at least one of radicalsR²⁹, R³⁰ and R³¹ is or contains an aromatic ring system having at least6 aromatic ring atoms; or from aromatic ring systems represented by thegeneral following formula (RS-d)

wherein R⁴⁰ to R⁴⁴ is at each occurrence, identically or differently,selected from H, a straight-chain alkyl group having 1 to 10 carbonatoms, or a branched or cyclic alkyl group having 3 to 10 carbon atoms,where the above-mentioned groups may each be substituted by one or moreradicals R³², or an aromatic ring system having 6 to 30 aromatic ringatoms, which may in each case be substituted by one or more radicalsR³², and where two or more of radicals R⁴⁰ to R⁴⁴ may be joined to forma (poly)cyclic alkyl group or an aromatic ring system, each of which maybe substituted by one or more radicals R³² as defined above.
 40. Thecompound according to claim 26, wherein the compound is selected fromthe compounds of formulae (5-1-1Y) to (5-3-Y7),

where the groups R^(A), R^(Y) and R have the same meaning as in claim26, and where in each of formulae (5-1-Y1) to (5-3-Y7), the phenylgroups indicated with —R³² are unsubstituted or substituted with one ormore radicals R³²; R⁴² and R⁴⁴ are at each occurrence, identically ordifferently, selected from H, a straight-chain alkyl group having 1 to10 carbon atoms, or a branched or cyclic alkyl group having 3 to 10carbon atoms, where the above-mentioned groups may each be substitutedby one or more radicals R³²; R³² is at each occurrence, identically ordifferently, selected from a straight-chain alkyl group having 1 to 10carbon atoms, or a branched or cyclic alkyl group having 3 to 10 carbonatoms, or an aromatic ring system having 6 to 24 aromatic ring atoms;with the proviso that at each occurrence at least one of radicals R²⁹,R³⁰ and R³¹ is other than H and that at each occurrence at least one ofradicals R²⁹, R³⁰ and R³¹ is or contains an aromatic ring system havingat least 6 aromatic ring atoms; or from aromatic ring systemsrepresented by the general following formula (RS-d)

wherein R⁴⁰ to R⁴⁴ is at each occurrence, identically or differently,selected from H, a straight-chain alkyl group having 1 to 10 carbonatoms, or a branched or cyclic alkyl group having 3 to 10 carbon atoms,where the above-mentioned groups may each be substituted by one or moreradicals R³², or an aromatic ring system having 6 to 30 aromatic ringatoms, which may in each case be substituted by one or more radicalsR³², and where two or more of radicals R⁴⁰ to R⁴⁴ may be joined to forma (poly)cyclic alkyl group or an aromatic ring system, each of which maybe substituted by one or more radicals R³² as defined above.
 41. Thecompound according to claim 37, wherein the groups R⁴⁰, R⁴², R⁴⁴ are ateach occurrence, identically or differently, selected from astraight-chain alkyl group having 1 to 10 carbon atoms, or a branched orcyclic alkyl group having 3 to 10 carbon atoms, where theabove-mentioned groups may each be substituted by one or more radicalsR³², R³² is at each occurrence, identically or differently, selectedfrom a straight-chain alkyl group having 1 to 10 carbon atoms, or abranched or cyclic alkyl group having 3 to 10 carbon atoms, or anaromatic ring system having 6 to 24 aromatic ring atoms; with theproviso that at each occurrence at least one of radicals R²⁹, R³⁰ andR³¹ is other than H and that at each occurrence at least one of radicalsR²⁹, R³⁰ and R³¹ is or contains an aromatic ring system having at least6 aromatic ring atoms; or from aromatic ring systems represented by thegeneral following formula (RS-d)

wherein R⁴⁰ to R⁴⁴ is at each occurrence, identically or differently,selected from H, a straight-chain alkyl group having 1 to 10 carbonatoms, or a branched or cyclic alkyl group having 3 to 10 carbon atoms,where the above-mentioned groups may each be substituted by one or moreradicals R³², or an aromatic ring system having 6 to 30 aromatic ringatoms, which may in each case be substituted by one or more radicalsR³², and where two or more of radicals R⁴⁰ to R⁴⁴ may be joined to forma (poly)cyclic alkyl group or an aromatic ring system, each of which maybe substituted by one or more radicals R³² as defined above.
 42. Aprocess for the preparation of the compound according to claim 26,comprising the following steps: (i) cyclisation reaction of atriarylamine compound substituted by at least one boronic acid or estergroup, in the presence of a halide compound, so that the boron atom ofthe boronic acid or ester group forms a six-membered ring with anadjacent aromatic or heteroaromatic group present in the triarylamineand where the boron atom is further substituted by a halogen; (ii)substitution reaction between the halogenated boron compound obtained instep (i) and a metal organyl reactant so that the halogen group on theboron atom is replaced by an organic group.
 43. A polymer, oligomer ordendrimer containing one or more compounds according to claim 26, wherethe bond(s) to the polymer, oligomer or dendrimer may be localised atany positions in formula (1) which is substituted by R¹, R², R^(A),R^(B) or R.
 44. A formulation comprising at least one compound accordingto claim 26 and at least one solvent.
 45. An Electronic devicecomprising at least one compound according to claim 26, selected fromthe group consisting of organic electroluminescent devices, organicintegrated circuits, organic field-effect transistors, organic thin-filmtransistors, organic light-emitting transistors, organic solar cells,dye-sensitized organic solar cells, organic optical detectors, organicphotoreceptors, organic field-quench devices, light-emittingelectrochemical cells, organic laser diodes and organic plasmon emittingdevices.
 46. An organic electroluminescent device comprising at leastone compound according to claim 26, wherein the compound is employed asan emitter in an emitting layer.
 47. The organic electroluminescentdevice according to claim 46, wherein the compound is employed as afluorescent emitter in an emitting layer, wherein the emitting layercomprises at least one further component selected from matrix materials.48. The organic electroluminescent device according to claim 46, whereinthe compound is employed as an emitter showing Thermally ActivatedDelayed Fluorescence in an emitting layer, wherein the emitting layercomprises at least one further component selected from matrix materials.49. The organic electroluminescent device according to claim 46, whereinthe compound is employed as a fluorescent emitter in an emitting layer,wherein the emitting layer comprises at least one sensitizer selectedfrom phosphorescent compounds and thermally activated delayedfluorescence compounds.
 50. The organic electroluminescent deviceaccording to claim 49, wherein the emitting layer further comprises atleast one organic functional material selected from matrix materials.